Superfund Record of Decision New London Submarine Base Soil and Sediment Area a Downstream Water Courses Overbank Disposal Area Groton CT


                                    EPA/ROD/R01-98/003
                                    1998
EPA Superfund
     Record of Decision:
     NEW LONDON SUBMARINE BASE
     EPA ID: CTD980906515
     OU03
     NEW LONDON, CT
     03/31/1998

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EPA 541-R98-003


                                                    RECORD OF DECISION
                                                           FOR
                                                     SOIL AND SEDIMENT
                                                  AREA A DOWNSTREAM WATER
                                              COURSES/OVERBANK DISPOSAL AREA

                                             NAVAL SUBMARINE BASE NEW LONDON
                                                    GROTON, CONNECTICUT

                                                 COMPREHENSIVE LONG-TERM
                                        ENVIRONMENTAL ACTION NAVY  (CLEAN) CONTRACT

                                                        Submitted to:
                                                      Northern Division
                                                 Environmental Branch Code  18
                                            Naval Facilities Engineering Command
                                           10 Industrial Highway, Mail Stop #82
                                               Lester, Pennsylvania 19113-2090


                                                        Submitted by:
                                                 Brown & Root Environmental
                                                  600 Clark Avenue, Suite 3
                                           King of Prussia, Pennsylvania 19406-1433

                                                          DECEMBER 1997

                                                        TABLE OF CONTENTS

SECTION                                                                                  PAGE  NO.

GLOSSARY	G-l

DECLARATION FOR THE RECORD OF DECISION	  1

1.0     SITE NAME, LOCATION AND DESCRIPTION	1-1

2 . 0     SITE HISTORY AND ENFORCEMENT ACTIVITIES	2-1
        2.1     LAND USE AND SITE HISTORY	2-1
        2.2     RESPONSE AND ENFORCEMENT HISTORY	2-1

3.0     COMMUNITY PARTICIPATION	3-1

4 . 0     SCOPE AND ROLE OF RESPONSE ACTION	4-1

5 . 0     SUMMARY OF SITE PHYSICAL/CHEMICAL CHARACTERISTICS AND ECOLOGY	6-1
        5 .1     PHYSICAL FEATURES AND ECOLOGICAL HABITAT	5-1
        5.1.1   Upper Pond	5-1
        5.1.2   OBDA Pond	5-2
        5.1.3   Lower Pond	5-2
        5.1.4   Stream 1	5-3
        5.1.5   Stream 2	5-3
        5.1.6   Stream 3	5-3
        5.1.7   Stream 4	5-4
        5.1.8   Stream 5	5-4
        5.1.9   Stream 6	5-4
        5 . 2     NATURE AND EXTENT OF CONTAMINATION	5-4

6 . 0     SUMMARY OF SITE RISKS	6-1
        6.1     CONTAMINANT IDENTIFICATION	6-1
        6 . 2     EXPOSURE ASSESSMENT	6-2
        6 . 3     TOXICITY ASSESSMENT	6-2
        6.4     RISK CHARACTERIZATION	6-3

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        6.4.1   Summary of Human Health Risk Characterization	6-3
        6.4.2   Summary of Ecological Risk Characterization	6-7
        6.4.3   Discussion of Uncertainty Factors	6-16
        6.5     CONCLUSION	6-18

7 . 0     REMEDIAL ACTION OBJECTIVES AND DEVELOPMENT OF ALTERNATIVES	7-1
        7 .1     STATUTORY REQUIREMENTS/RESPONSE OBJECTIVES	7-1
        7 . 2     TECHNOLOGY SCREENING AND ALTERNATIVE DEVELOPMENT	7-2

8 . 0     DESCRIPTION OF ALTERNATIVES	8-1
        8.1     ALTERNATIVE 1: NO ACTION	8-1
        8.2     ALTERNATIVE 2: CAPPING, RESTORATION OF WETLANDS AND
                WATERWAYS, AND INSTITUTIONAL CONTROLS	8-1
        8.3     ALTERNATIVE 3: EXCAVATION/DREDGING, ONSITE DEWATERING, AND
                OFFSITE DISPOSAL OF SOIL/SEDIMENT; RESTORATION OF
                WETLANDS AND WATERWAYS; AND MONITORING	8-3
        8.4     ALTERNATIVE 4: EXCAVATION/DREDGING, ONSITE DEWATERING AND
                THERMAL DESORPTION OF SOIL/SEDIMENT; ONBASE REUSE OF
                TREATED SOIL; OFFSITE DISPOSAL OF SEDIMENT; RESTORATION OF
                WETLANDS; AND MONITORING	8-5

9 . 0     SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES	9-1
        9 .1     EVALUATION CRITERIA USED FOR DETAILED ANALYSIS	9-1
        9.1.1   Threshold Criteria	9-1
        9.1.2   Primary Balancing Criteria	  9-1
        9.1.3   Modifying Criteria	9-2
        9 . 2     COMPARATIVE ANALYSIS OF ALTERNATIVES	9-2
        9.2.1   Overall Protection Of Human Health And Environment	9-3
        9.2.2   Compliance With ARARs And TBCs	9-4
        9.2.3   Long-Term Effectiveness and Permanence	9-5
        9.2.4   Reduction of Toxicity, Mobility, and Volume Through Treatment	9-5
        9.2.5   Short-Term Effectiveness	9-6
        9.2.6   Implementability	9-6
        9.2.7   Cost	9-7
        9.2.8   State Acceptance	9-8
        9.2.9   Community Acceptance	9-8

10 . 0    THE SELECTED REMEDY	10-1

11. 0    STATUTORY DETERMINATIONS	11-1
        11.1    PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT	11-1
        11.2    COMPLIANCE WITH ARARs	11-1
        11. 3    COST EFFECTIVENESS	11-1
        11.4    UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
                OR RESOURCE RECOVERY TECHNOLOGIES TO THE MAXIMUM EXTENT
                PRACTICABLE	11-8
        11.5    PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT	11-9

12 . 0    DOCUMENTATION OF NO SIGNIFICANT CHANGES	12-1

13.0    STATE ROLE	13-1

REFERENCES	R-l

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                                                        TABLES
NUMBER
                                                                                        PAGE NO.
5-1     Summary of Soil Analytical Results	5-7
5-2     Summary of Sediment Analytical Results Zones 1 Through 4	5-11
5-3     Summary of Sediment Analytical Results Off site Reference Areas 1	5-15
6-1     Estimated Human Health Risks	6-5
6-2     Summary of Human Health Chemicals of Concerns (COGS)	6-8
6-3     Receptor-Specific Remediation Goals	6-9
6-4     Summary Of Potential Chemical-Specific Risks To Ecological Receptors Of Concern	6-10
6-5     Summary Of Sediment Triad Ranking	6-12
6-6     Remediation Goals for Inorganic Contaminants of Concern Compared to Average/Maximum
        Concentrations in Sediments	6-15
10-1    Summary of Remediation Goals Protective of Human and Ecological Receptors of
        Concern	10-7
11-1    Assessment of Chemical-Specific ARARs and TBCs Alternative 3 - Excavation/Dredging,
        Onsite Dewatering, and Offsite Disposal of Soil/Sediment; Restoration of Wetlands and
        Waterways; and Monitoring	11-2
11-2    Assessment of Location-Specific ARARs and TBCs Alternative 3 - Excavation/Dredging,
        Onsite Dewatering, and Offsite Disposal of Soil/Sediment; Restoration of Wetlands and
        Waterways; and Monitoring	11-4
11-3    Assessment of Action-Specific ARARs and TBCs Alterative 3 - Excavation/Dredging,
        Onsite Dewatering, and Offsite Disposal of Soil/Sediment; Restoration of Wetlands and
        Waterways; and Monitoring	11-6

                                                        FIGURES

NUMBER                                                                                  PAGE NO.

1-1     Site Vicinity Map	1-2
1-2     Site Map	1-3
1-3     Site Layout, Topography, and Zone Designation Map	1-4
7-1     Estimated Area of Soil Excavation	7-3
7-2     Estimated Area of Sediment Excavation	7-4
10-1    Conceptual Remediation Plan	10-2
10-2    Conceptual Design of Dewatering Pad/Wastewater Treatment	10-4

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GLOSSARY

ARARs - Applicable or relevant and appropriate requirements of all state and federal laws for particular
conditions or cleanup options at a site.

Bench-scale Treatability Study - A scientific and engineering experiment that is conducted in a
laboratory with samples of contaminated media from the site to find out: (1) how to remove the
contaminants and (2) how to improve the physical nature of the material (such as removal of excess water)
for implementing the remedy.

CERCLA - The Comprehensive Environmental Response, Compensation, and Liability Act is a federal law
passed in 1980 and amended by Congress by the Superfund Amendments and Reauthorization Act of 1986. The
law established a national trust fund (known as Superfund) to investigate and remediate abandoned or
uncontrolled hazardous waste sites.

Contaminant - Any physical, chemical, biological, or radiological substance or matter that, at certain
levels, could have an adverse effect on human health or the environment.

FS - The Feasibility Study (FS) is the development and analysis of potential remedial alternatives that
address all operable units, or environmental media at a site. The technologies evaluated for development
of remedial alternatives are not limited to those that are commercially available and proven.

FFS - The Focused Feasibility Study (FFS) is the development and analysis of potential remedial a
alternatives for only one operable unit (such as soils or sediment) and normally includes a few selected
remedial alternatives that use commercially available, proven technologies.

FETAX Test - A frog embryo toxicity test that measures the effects of contaminants on growth and
occurrence of abnormalities.

Free Water - Naturally occurring groundwater/surface water physically trapped in the interstitial space
of soil/sediment particles.

Installation Restoration Program (IRP) - The program established by the Department of Defense in 1975 to
investigate, identify, and clean up hazardous waste contamination at federal facilities.

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DECLARATION FOR THE RECORD OF DECISION

SITE NAME AND LOCATION

Area A Downstream Water Courses/Overbank Disposal Area (Area A Downstream/OBDA) is located on the Naval
Submarine Base New London (NSB-NLON) , Groton, Connecticut. This Record of Decision (ROD) addresses the
contaminated soil and sediment at this site. This Record of Decision does not address contaminated
groundwater, which will be addressed as a separate operable unit at a later time.

STATEMENT OF BASIS AND PURPOSE

This ROD presents the following final remedy for soil and sediment at Area A Downstream/OBDA:

• Removal of surface water followed by treatment and discharge to Thames River.

• Excavation of contaminated soil and sediment, followed by onsite dewatering and disposal at
an offsite landfill.

The selected remedial action was chosen in accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) of 1980, as amended by the Superfund Amendments and
Reauthorization Act (SARA) of 1986, and to the extent practicable, the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP). This decision is based on the administrative record for Area
A Downstream/OBDA which was developed in accordance with Section 113(k) of CERCLA, and is available for
public review. By excavation and removal of the contaminated soil and sediment, the U.S. Navy plans to
remedy the potential threat to human health and ecological receptors.

The Connecticut Department of Environmental Protection (CTDEP) , concurs with the selected remedy for Area
A Downstream/OBDA.

ASSESSMENT OF AREA A DOWNSTREAM/OBDA

Actual or threatened releases of hazardous substances from this site, if not addressed by implementing
the response action selected in this ROD, may present a current or potential threat to public health,
welfare, or the environment.

The U.S. Navy has determined that remedial action is necessary for this site because the potential human
health risks associated with the soil and sediment at this site exceed the U.S. EPA limit of cumulative
noncarcinogenic Hazard Index (HI) of 1.0. Also the risks for these potential receptors exceed Connecticut
Department of Environmental Protection's (CTDEP) Remediation Standards limit of 1 x 10 -6 Incremental
Cancer Risk (ICR) for individual contaminants with a cumulative ICR exceeding 1 x 10 -5 and cumulative HI
exceeding 1.0. Although there are currently minimal human health risks posed by the site, this ROD
selects the remedy to address potential future risks to humans.

The ecological risk assessment concluded that exposure to surface water and sediment concentrations of
DDT and its metabolites ODD and DDE, and to a lesser extent, dieldrin, were responsible for adverse
ecological effects to aguatic biota, in particular sediment-dwelling organisms. Terrestrial vertebrates
are also at risk from exposure to DDT and its metabolites in soil as a result of indirect exposure
through consumption to contaminated prey.

DESCRIPTION OF THE SELECTED REMEDY

This remedial action addresses the soil and sediment at the Area A Downstream/OBDA. The groundwater at
this site will be addressed as a separate operable unit at a later time.

The U.S. Navy has determined that excavation and off site landfill disposal is appropriate for the
contaminated soil and sediment at this site. Potential exposure to these media is the principal threat
posed by the site. This remedy involves removal, treatment, and discharge of surface water; excavation of
contaminated soil and sediment; onsite dewatering to remove free water in the soil and sediment;
treatment and discharge of removed water; and offsite disposal of the dewatered media at approved
landfills.

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STATUTORY DETERMINATIONS

The remedy selected by the U.S. Navy for Area A Downstream/OBDA is protective of human health and the
environment,  complies with federal and state requirements that are legally applicable or relevant and
appropriate requirements to this remedial action, and is cost-effective. Because this remedy will not
result in contaminants remaining in soil and sediment on site above healthy- or ecologically-based
levels, the 5-year review process will not apply to this action. This remedy uses permanent solutions and
alternative treatment technologies to the maximum extent practicable for this site. The selected remedy
does not satisfy the statutory preference for remedies that employ treatment as a principal element to
reduce toxicity, mobility, or volume of contaminants. However, the selected remedy is deemed to be cost
effective.

DECLARATION

This ROD represents the selection of a remedial action under CERCLA for Area A Downstream/OBDA. The
foregoing represents the selection of a remedial action by the Department of the Navy and the United
States Environmental Protection Agency Region I with the concurrence of the Connecticut Department of
Environmental Protection.

Concur and recommend for immediate implementation:

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1.0 SITE NAME, LOCATION AND DESCRIPTION

NSB-NLON covers approximately 550 acres of land in the southeast of Connecticut in the towns of Ledyard
and Groton, on the east bank of the Thames River, approximately 6 miles north of Long Island Sound. For
almost 100 years, the Naval Submarine Base New London (NSB-NLON) has served as a major support center for
the U.S. Atlantic fleet. The location of NSB-NLON is shown as the U.S. Naval Reservation Figure 1-1.

STREAMS AND PONDS

The Area A Downstream/OBDA drains the Area A Landfill and Area A Wetland through water bodies and streams
that ultimately flow into the Thames River. The Area A Downstream/OBDA includes three small ponds (Upper
Pond, Lower Pond, and OBDA Pond) plus six interconnected streams (Streams 1 through 6). The location of
the Area A Downstream/OBDA is shown on Figure 1-2. The site layout and topography of the Area A
Downstream/OBDA is shown on Figure 1-3. The zone designations (Zone 1 through Zone 6) shown on Figure 1-3
were the subdivisions of the site that were used during sampling of media in the Phase II RI.

The primary discharge point from the Area A Wetland is from four large culverts through a dike that
separates the wetland from the Area A Downstream/OBDA. This discharge forms a small stream (Stream 4),
which flows west for approximately 200 feet into Upper Pond. Upper Pond discharges to Stream 3, which
flows north and then west toward Triton Road (past the OBDANE site) to the entrance of the Torpedo Shops.
Stream 3 then meets the drainage channel from the Torpedo Shops and forms Stream 5. Stream 5 flows west
along Triton Avenue through the Small Arms Range and under Shark Boulevard and eventually discharges to
the Thames River at the DRMO outfall. Upper Pond also has a discharge structure on the south side. During
periods of high flow and high water at the pond, water also flows out through this structure to Stream 1,
which flows west from OBDA Pond. A second pond (Lower Pond), northwest of Upper Pond, is formed by
groundwater inflow and discharges to Stream 2, which enters a storm sewer and flows to the west around
North Lake.

Groundwater also seeps from the northwest slope of the adjacent Area A Landfill into a small pond (OBDA
Pond) located at the base of that slope, which is the continuation of the dike which separates the Area A
Wetland from the Area A Downstream/OBDA. Stream 1 flows from this OBDA Pond west toward North Lake, a
recreational swimming area for Navy personnel, enters a culvert, which bypasses North Lake and discharges
to a stream (Stream 6) below the outfall of that lake. Stream 6, which is formed by Stream 1, Stream 2,
and the outflow of North Lake, flows west under Shark Boulevard and through the golf course to the Thames
River. North Lake is filled with potable water every year and drained at the end of the season. Surface
water levels in North Lake do not appear to coincide with groundwater levels in adjacent monitoring
wells. Therefore, there seems to be little hydraulic connection between surface water in North Lake and
the shallow groundwater.

OVERBANK DISPOSAL AREA (OBDA)

The OBDA is located at the base of the northwest slope of the adjacent Area A Landfill where the angle of
the slope approaches 45 degrees. A small wetland exists at the very base of the slope. This area was used
as a disposal site after the earthen landfill slope/dike was constructed in 1957. The Initial Assessment
Study (IAS) report (Envirodyne, 1982) indicated that the disposed of material had been there for many
years. The IAS report also indicated that the materials were not covered and included 30 partially
covered 200-gallon metal fuel tanks and scrap lumber. Approximately 30 empty, unlabeled, 200 gallon
tanks, old creosote telephone poles, several empty unlabeled 55-gallon drums, and rolls of wire were
observed at that time. Orange-colored sediment were also observed in the water discharging from the base
of the Area A landfill slope embankment. The above mentioned debris were removed as part of a removal
action in March 1997 and some of the debris (such as acetylene tanks) were characterized as hazardous.
The debris was disposed of at suitable landfills or recycling facilities offsite according to the Final
Removal Action Report (Foster Wheeler, July 1997).

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES

This section summarizes the land use, response history, and enforcement history for the Area A
Downstream/OBDA.

2.1 LAND USE AND SITE HISTORY

For almost 100 years, the NSB-NLON has served as a major support center for the U.S. Atlantic fleet. To
protect its employees and residents, the NSB-NLON has historically used pesticides for control of
mosguitoes that breed in the Area A Downstream/OBDA wetlands and water courses and affect the adjacent
recreational areas of North Lake and the golf course. Also, as part of its naval operations, on occasion,
the NSB-NLON has dredged the Thames River and placed the dredge spoil at the current location of the Area

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A Wetland and Area A Landfill, a process during which some of that dredge spoil could have been carried
over by natural forces (storm water and streams) into the adjacent Area A Downstream/OBDA.

The main cause of contamination at the Area A Downstream/OBDA was the application of pesticides. These
pesticides were reportedly applied on the surface of water bodies to control mosguito proliferation
adjacent to the nearby base recreational facilities (North Lake and golf course). Additional contaminants
are the inorganic constituents of the over dredge spoil which have been carried over from adjacent sites.

Samples of surface soil (typically within a depth of 0 to 2 feet or less than 3 feet below the surface)
and sediment showed the presence of mainly DDT, ODD, DDE, and small amounts of other pesticides such as
dieldrin. Samples of sediment also contained relatively higher levels of several metals (such as arsenic,
beryllium, cadmium, lead and zinc) as compared to less contaminated reference areas outside the site.

Surface water samples contained low concentrations of some of the same contaminants as those present in
the soil and sediment.

2.2 RESPONSE AND ENFORCEMENT HISTORY

The IRP and CERCLA. In 1975, the Department of Defense developed a program to investigate and clean up
problem areas involving contamination of land and water at federal facilities such as the NSB-NLON. That
program, known as the Installation Restoration Program (IRP), is being conducted in accordance with the
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) , commonly referred to as
the Superfund law. In 1986, Congress passed amendments to CERCLA that contain provisions for federal
facilities (see Section 120). NSB-NLON was placed on the National Priorities List (NPL) of federal
Superfund sites on August 30, 1990, by the U.S. Environmental Protection Agency (U.S. EPA).

Initial Assessment Study (IAS). An IAS (Envirodyne, 1982) was conducted to identify and evaluate past
hazardous waste disposal practices at NSB-NLON and to assess the associated potential for environmental
contamination. The IAS recommended further investigation of several areas including Area A
Downstream/OBDA.

Federal Facility Agreement (FFA). The U.S. Navy entered into an FFA with the EPA and the Connecticut
Department of Environmental Protection (CTDEP) January 5, 1995. The FFA established roles and
responsibilities of each agency, set deadlines for the investigation and cleanup of hazardous waste
sites, and established a mechanism for the resolution of disputes among agencies.

Remedial Investigations and studies conducted to date. A Phase I Remedial investigation(RI) (Atlantic,
1992), a Phase II RI (B&R Environmental, March 1997), a Focused Feasibility Study (FFS, Atlantic 1994)
(including additional investigation and a bench-scale treatability study), and a Wetlands Functions and
Values Assessment (Niering and Brawley, 1997) were conducted over the course of several years, ending in
May 1997. A feasibility study on the soil and sediment at the site (Brown & Root Environmental, July
1997) was prepared by the Navy to support the Proposed Plan, incorporating the significant findings of
all of these studies and responds to the comments made by the State of Connecticut and U.S. EPA an the
prior version of FFS.

Feasibility Study (FS). The latest version of the FS for this site (B&R Environmental, July 1997) is the
basis of the Proposed Plan. The scope of this FS is limited to the soil and sediment at the site.
However, this FS also addresses reduction of any adverse affects that the soil and sediment may have on
groundwater and surface water. This FS does not consider groundwater, which will be evaluated as part of
a separate upcoming study. This FS only considers surface water to the extent necessary for the
remediation of sediment.

3.0 COMMUNITY PARTICIPATION

Throughout the history of the contamination investigations and enforcement activities at NSB-NLON, the
community has been actively involved. Community members and other interested parties have been kept
abreast of site activities through informational meetings, published "fact sheets and information
updates," press releases, public meetings, and Technical Review Committee (TRC) and Restoration Advisory
Board (RAB) meetings.

The TRC was established in 1988 and was later (in 1994) reorganized and renamed the RAB. The RAB
(formerly TRC) has been an important vehicle for community participation in the NSB-NLON IRP. The RAB
consists of representatives of the U.S. Navy, EPA, CTDEP, planners and officials of neighboring towns,
Navy and EPA contractors, and local residents with scientific knowledge of or interest in the sites.

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The RAB meets regularly to review technical aspects of the NSB-NLON IRP and provides a mechanism for
community input to the program.

To ensure that the community is well informed about NSB-NLON IRP activities, the Navy has provided and
will continue to provide the public with the following sources or vehicles of information.

       •      Public Information Repositories.  The Public Libraries in Groton and Ledyard,  the Naval
              Submarine Base,  and New London are the designated information repositories for the Subbase
              IRP.

       •      Key Contact Persons.  The Navy has designated a Public Affairs Officer and an EPA Community
              Involvement Coordinator as information contacts for the  Subbase.  Their addresses and phone
              numbers are included in all information material distributed to the public,  including any
              fact sheets and press releases.  The Public Affairs Officer will maintain the site mailing
              list to ensure that all interested individuals receive more pertinent information on the IRP
              activities.

       •      Mailing List.  To ensure that information materials reach the individuals who are interested
              in or affected by the IRP activities at the Subbase,  the Navy maintains and will regularly
              update a mailing list of interested persons.  Anyone interested in being placed on the list
              can do so by contacting the Subbase Public Affairs Officer.

       •      Regular Contact with Local Officials.  The Navy has managed and will continue to arrange
              regular meetings to discuss the status of the IRP with the RAB,  which includes
              representatives from neighboring towns.  The Navy contacts other town officials on an
              as-needed basis.

       •      Press Releases and Public Notice.  The Navy has issued and will continue to issue press
              releases to local media sources to announce public meetings and comment periods,  the
              availability of the IRP reports and plans,  and to provide general information updates as and
              when the Public Affairs Officer sees fit.

       •      Public Meetings.  The Navy has held and will continue to  hold informal public meetings as
              needed to keep residents and town officials informed about IRP activities at the Subbase,
              and of significant milestones in the IRP. The meetings include presentations by Navy
              technical staff,  EPA personnel,  and/or support contractors for both agencies.  The meetings
              also include a guestion-and-answer period.  Minutes of meetings during public comment periods
              are included in the Administrative Record for public reference.

       •      Fact Sheets and Information Update. The Navy has been developing a series of fact sheets
              which are mailed to public officials and other interested individuals and/or used as
              handouts at the public meetings.  Each fact sheet includes a schedule of upcoming meetings
              and other site activities. The fact sheets may explain why the Navy is conducting certain
              activities or studies,  update readers on potential health risks,  or provide general
              information on the IRP process.

A detailed formal NSB-NLON Community Relations plan was published in February of 1994. The plan
identifies issues of community interest and concern regarding the NSB-NLON. The plan also describes a
program of community relations activities that the Navy will conduct during the IRP.

The activities of the community relations program outlined in this plan have the following specific
objectives:  (1) to keep local officials, citizens, military personnel, and the media informed of site
activities;  (2) to increase community awareness of the goals and procedures of the IRP; and  (3) to
provide opportunities for public involvement in the cleanup process.

The information in the Community Relations Plan is based upon:

       •      interviews with area residents and local officials conducted in Groton and Ledyard on
              October 2-3,  1991,

       •      interviews with area residents and local officials conducted by phone in September and
              October of 1991;

       •      input of the TRC or RAB which had regularly met to discuss progress at the Subbase;

       •      public comments and guestions at public information meetings held in 1990 and 1991;

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       •      review of Navy site files;  and

       •      discussions held with Navy,  EPA,  contractors,  and technical and public affairs staff.

The U.S. Navy published a notice and brief analysis of the Area A Downstream/OBDA Proposed Plan in the
New London Day on August 1, 1997, and made the Proposed Plan available to the public at the Groton Public
Library, Groton, Connecticut, and the Bill Library, Ledyard, Connecticut.

From August 1, 1997 through September 1,  1997,  the U.S. Navy held a 30-day public comment period to
accept public input on the alternatives presented in the FS and the Proposed Plan, as well as other
documents previously released to the public. On August 6, 1997, NSB-NLON personnel and regulatory
representatives held a public meeting to discuss the Proposed Plan, answer guestions and concerns
regarding the site and the remedial alternative under consideration, and accept any oral comments. The
Navy did not receive any written comments from the public during the 30-day public comment period. The
U.S. Navy received a letter dated August 18, 1997 from the CTDEP expressing their support of the Proposed
Plan as presented. A transcript of this meeting is included as Appendix A, a copy of CTDEP's letter is
included as Appendix B, a Responsiveness Summary is included as Appendix C, and the Declaration of
Concurrence is included as Appendix D.

                               4.0 SCOPE AND ROIiE OF RESPONSE ACTION

The U.S. Navy has placed 25 sites at this base under the purview of the Installation Restoration Program.

Depending on the characteristics of the sites,  the media of concern at these sites are: soil and
sediment, groundwater, surface water, and air.  Records of Decision have been issued for some of these
sites, and of these sites remedial action has been completed at a few. The remaining sites are under
various stages of remedial investigation and feasibility study preparation.

The scope of the remedial action at the Area A Downstream/OBDA is limited to the soil and sediment at the
site. As identified in the Phase II RI (B&R Environmental, March 1997), samples of media collected in
stream beds, pond bottoms, and associated wetlands in the vicinity of these water bodies are assumed to
be sediments and the solid media outside of the sediments are assumed to be soil. The remedial action was
selected among a total of four alternatives retained for detailed screening in the FS for this site,
including No Action. Although groundwater will not be remediated at that time, the cross-media impact
from contaminated soil and sediment would be minimized by the alternative selected in this ROD.

Groundwater will be addressed as a separate operable unit at a later time.

The selected alternative is excavation of the contaminated soil and sediment followed by disposal at an
offsite landfill. All of the groundwater and surface water seepage into the site from the adjacent Area A
Wetland and Area A Landfill will be diverted to bypass the areas of proposed excavation and discharged
into downstream culverts. Stream diversion details will be decided during remedial design. Erosion and
sediment controls will also be addressed during remedial design. From the downstream culverts, the
combined groundwater/surface water will be allowed to discharge to Thames River as before. Standing water
in the ponds and streams on site will be pumped, treated, and discharged to Thames River.

Following groundwater and surface water management, the stream beds, pond beds, adjacent wetland areas,
and soils lhat have been determined to be contaminated at levels exceeding remediation goals will be
excavated. The excavated material is expected to contain significant levels of free water that will need
to be removed to improve handling and reduce disposal costs. Removal of free water to the extent
practicable will be accomplished by stockpiling the excavated material on dewatering pads at a nearby
location. The wastewater  (drainage) from the dewatering operation will be collected in a sump, treated,
and discharged to Thames River.

The dewatered soil and sediment will be transported offsite for disposal at suitable landfills. A portion
of the material containing relatively higher concentrations of contaminants that may not be accepted in a
nonhazardous waste landfill, will be disposed of at a hazardous waste landfill.

Following excavation and disposal of contaminated sediments and soils, the excavated areas will be
backfilled with clean fill with comparable organic content to the excavated sediments and soil. During
remedial design, alternative methods of erosion control  (e.g. placement of hay bales or vegetative
matting) will be considered for stream beds and pond banks. For areas outside the stream and pond beds,
erosion control will consist of mainly top soil and revegetation of species of plants similar to those
existing and those favorable to wetland recovery.

-------
The diversions to the surface water and groundwater inflow to the area will be discontinued, and flow
will be routed through the restored waterways. The functions and values of the wetland communities
associated with the site will be replaced in accordance with state and federal standards, as determined
during remedial design.

5.0 SUMMARY OF SITE CHARACTERISTICS AND ECOLOGY

Section 1.0 of the FS (B&R Environmental, July 1997) contains an overview of the Area A Downstream/OBDA,
including discussions on the geology, hydrogeology, ecological habitat, and nature and extent of
contamination. The RI Report (B&R Environmental, March 1997) contains the detailed results of the
investigations at this site. The significant findings of the RI are summarized below.

5.1 PHYSICAL FEATURES AND ECOLOGICAL HABITAT

Area A Down stream/OBDA is contained in a small, narrow, steep-sided valley located in the northern
portion of the NSB-NLON. The upper end of this valley was dammed to provide a disposal area for dredge
spoil, eventually forming what is now known as the Area A Wetland.

The soil at the site consists of natural overburden deposits (silt, sand and gravel) overlying
metamorphic bedrock. Groundwater is present in the overburden and bedrock, and flows towards the Thames
River.

The site primarily consists of scrub-shrub and forested wetlands characterized by a canopy dominated by
hardwoods (primarily oaks) and a secondary mixed hardwood forest dominates the wetland edge. Understory
vegetation present in the area includes laurel, dogwood, cherry, tupelo, sassafras and other tree
saplings, catbriar, and grape vine.

Three small ponds (Upper Pond, Lower Pond, and OBDA Pond) and six small streams (Streams 1 through 6) are
present at the site. The marine sediment contained in the Area A Wetland influences water guality in
these waterbodies; as elevated salinity was routinely recorded during surface water measurements taken at
the site. The ephemeral nature of the streams and the shallowness of the ponds makes them unsuitable
habitat for fish. No rare or endangered species of flora or fauna have been recorded in previous
investigations such as the Phase II RI (B&R Environmental, 1997a) and the Functions and Values Assessment
(Niering and Brawley, 1997).

5.1.1 Upper Pond

Upper Pond and its associated wetland (0.48 acre) are located approximately 300 ft downstream of the Area
A Wetland. Upper Pond is a palustrine open water (shallow) wetland surrounded by a palustrine emergent,
nonpersistent, narrow-leaved wetland with an artificial water regime (Atlantic, July 1994).

Water depth has been reported to range from approximately 1.5 to 4 feet. Upper Pond is characterized by
poorly to very poorly drained fine-textured marine sediment that were naturally transported into this
pond from the upgradient Area A Wetland. The sediment are very fine and are generally unconsolidated. A
layer of decomposing leaves and two submerged aguatic plants, duckweed and water starwort cover most of
the pond's sediment. The emergent, persistent, narrow-leaved vegetation is dominated by the common reed
(Phragmites australis). While frogs and turtles have occasionally been observed in the pond, the results
of surveys have demonstrated that the Upper Pond does not contain fish.

5.1.2 OBDA Pond

OBDA Pond and it associated wetland habitat (1.29 acre) are located below the northwest slope of the
adjacent Area A Wetland which extends to the dike that forms the Area A Wetland. OBDA Pond is
approximately 150 ft west of the Area A Wetland and 50 to 250 ft south of Upper Pond and Lower Pond.

This pond is classified as a palustrine emergent, nonpersistent, narrow-leaved wetland surrounded by
scrub/shrub and forested broad-leaved deciduous wetland with a nontidal seasonal water regime (Atlantic,
July 1994). The emergent, nonpersistent, narrow-leaved vegetation is dominated by a monotypic stand of
the common reed (P. austrafis). Sweet pepperbush, highbush blueberry, and red maple are some of the
prevalent shrub and tree vegetation species surrounding the pond. The sediment in OBDA Pond and the
surrounding wetland area are classified as native Ridgebury fine sandy loam which are poorly drained,
moderately coarse textured, glacial till soil developed over compact till. The pond's primary source of
water is groundwater, and the sediment are generally covered by an iron floe. Water is generally 1 to 1.5
feet deep. No fish are present in OBDA Pond, but amphibians such as frogs have occasionally been observed
along the pond's shoreline.

-------
5.1.3 Lower Pond

Lower Pond (0.50 acre) is located approximately 50 ft downstream of Upper Pond. Lower Pond is classified
as a palustrine open water (shallow) wetland surrounded by a palustrine scrub/shrub and wooded
broad-leaved, deciduous wetland (Atlantic, July 1994). This pond has a seasonal water regime; standing
water is generally present in the pond only during the winter and spring. Sweet pepperbush, highbush
blueberry, and red maple dominate the vegetation of this area. The soils associated with Lower Pond and
its surrounding wetland are classified as native Ridgebury fine sandy loam which are poorly drained,
moderately coarse textured, glacial till soil developed over compact till. A thick layer of decomposing
and partially decomposed leaves covers the pond's sediment. Upper Pond and its associated wetland are
adjacent to a smaller disturbed wetland (0.027 acre) with similar characteristics and dominant
vegetation. Neither fish nor amphibians have been observed in Lower Pond. The Lower Pond is considered to
be the least disturbed area at this site, and is currently serving the greatest number of positive
wetland functions and values (Niering and Brawley, 1997).

5.1.4 Stream 1

Stream 1 is located on the southern side of the valley containing the site. Stream 1 drains OBDA Pond,
travels along the length of the site, and exits into Stream 6 on the western side of North Lake. Stream
1, like the other streams in the site, can be categorized as a low energy, first order stream. During the
spring of 1995, the stream ranged from 1.5 to approximately 3 feet wide and 4 to 8 inches deep. The
southern portion of the site is heavily canopied and the stream's bottom is covered by a thick, mat of
decomposing leaf litter and detritus. No hard substrate (e.g., gravel or cobble) was observed in this
stream. No riffle habitat and few leaf packs were observed. Thirty-nine vegetative species were recorded
in the upper portion of the stream (Niering and Brawley, 1997).

5.1.5 Stream 2

Stream 2 is located in the center of the site and serves as the outlet for Lower Pond. Like Stream 1,
this stream is also a small, low energy, first order stream. The substrates are highly organic and are
composed of partially decomposed leaves and detritus. Stream 2 is approximately 2 feet wide and 4 to 8
inches deep. The stream was characterized by small pools and a few areas that could be categorized as
riffles. No hard substrate (e.g., gravel or cobble) was observed. Stream 2 enters into a storm sewer and
discharges into Stream 6. Stream 2 is noted to be the least disturbed of streams at this site and
traverses a relatively mature wooded area consisting of red maple, white ash, black gum, high bush
blueberry, and sweet pepperbush (Niering and Brawley, 1997).

5.1.6 Stream 3

Stream 3 is located along the northern boundary of the site and serves as the outlet stream for Upper
Pond. Stream 3 is an artificially constructed water course characterized by relatively hard-packed
substrates and a relatively deep, steep-sided channel that cuts through marine sediment apparently washed
into the site from the Area A Wetland. The substrates consist of a combination of fine clay and sand.
During the spring of 1995, Stream 3 was approximately 3 feet wide and 8 to 12 inches deep. Little organic
matter was present in this small stream, and no riffle or pool habitats were observed. Stream 3 feeds
into Stream 5 which flows along Triton Avenue. Stream 3 exhibits a high overall species richness (40
vegetative species recorded) that are typical of disturbed non-wetland sites (Niering and Brawley, 1997).

5.1.7 Stream 4

Stream 4 is located at the eastern end of the site and serves as the outlet for the Area A Wetland. Water
drains from the Area A wetland through a standpipe and into Stream 4. Stream 4 is also an artificially
constructed water course like Stream 3, and the substrates are characterized by a hard-packed clay with
little coarse (e.g., sand or gravel) material present. Portions of the stream's bed are covered with iron
floe.

No organic matter (e.g., leaf packs) was observed in this stream nor is Stream 4 characterized by a
riffle or pool habitat. In the spring of 1995, Stream 4 was approximately 6 to 8 inches deep and 3 to 4
feet wide. Stream 4 drains into Upper Pond. Stream 4 also exhibits a high overall special richness like
Stream 3, that are typical of disturbed non-wetland sites (Niering and Brawley, 1997).

5.1.8 Stream 5

Stream 5 is located along Triton Avenue which is on the northern side of the valley containing the site.

Stream 5 begins at the confluence of Stream 3 and the drainage channel from the Torpedo Shops. Stream 5
flows through a series of unlined channels and culverts and discharges directly into the Thames River

-------
near the DRMO. Stream 5 has not been comprehensively studied like Streams 1 through 4, and little flow,
substrate, and habitat information is known about the stream.

5.1.9 Stream 6

Stream 6 is located in the southwestern corner of the site. Stream 6 begins at the confluence, of Stream
1, Stream 2, and the outlet of North Lake; travels through the golf course in a series of concrete-lined
channels and culverts; and discharges into the Thames River just north of Site 22 (Pier 33). Stream 6,
like Stream 5, has not been comprehensively studied like Streams 1 through 4, and therefore little flow,
substrate, and habitat information is known about the stream. However, because the stream is primarily a
man-made series of concrete-lined channels and culverts, it offers little ecological habitat.

5.2 NATURE AND EXTENT OF CONTAMINATION

Soil, sediment, and surface water samples were taken and analyzed for organic and inorganic contaminants.
The soil data is limited to a few surface (i.e., sample depth of 0 to 2 feet below surface) and
subsurface (i.e., sample depths to 5 feet below the surface) samples. The most significant contaminants
in soil were noted to be pesticides and certain metals. The pesticides consisted mainly of 4,4'-DDD,
4,4'-DDE and 4,4'-DDT, i.e. DDT and metabolites or DDT residuals (DDTR) . DDTR were detected in all
surface soil samples. The highest concentrations of DDTR were detected in Zone 1 (the vicinity of the
OBDA Pond and Upper Pond) at the following levels 4,4'-DDT (1,400,000 Ig/kg), 4,4'-ODD (240,000 Ig/kg),
and 4,4'-DDE (24,000 Ig/kg). In surface soil, aluminum, cadmium, chromium, cobalt, manganese, nickel, and
zinc were detected sporadically at concentrations that exceeded their respective maximum background
concentrations, but, within the order of magnitude of their respective maximum background concentrations.
No pattern of metal contamination that may be indicative of a source was apparent for any of the metals,
except for manganese. However, manganese is noted to be a naturally occurring mineral constituent in the
geology of the Subbase NLON (Phase II RI, pp 4-8). Although certain volatile organic compounds (VOCs) and
semivolatile organic compounds (SVOCs) were also detected, the detections were few, and the levels were
relatively insignificant.

The most significant contaminants in sediment were DDTR and to a lesser extent, inorganics. The following
are the salient features of the contamination in the sediment:

• Zone 1 (OBDA Pond, Stream 1 and Associated Wetlands): DDTR were detected in a majority of
sediment samples. Maximum concentrations of 4,4'-ODD at 300,000 Ig/kg and 4,4'-DDE at
15,000 Ig/kg, respectively, were detected in an OBDA Pond sediment sample. The maximum
concentration of DDT of 94,000 Ig/kg was detected in a Stream 1 sediment sample. Five other
pesticides were also detected at lower concentrations, including a maximum of 370 Ig/kg of
dieldrin in a Stream 1 sediment sample. Inorganics were detected in a majority of sediment
samples at the following maximum concentrations: arsenic (39.9 mg/kg), lead (223 mg/kg),
cadmium (30.1 mg/kg), manganese (2,850 mg/kg), and zinc (2,720 mg/kg). Arsenic, in
particular, is noted to have been detected at concentrations significantly exceeding an
offsite reference sample concentration of 4.4 mg/kg.

• Zone 2 (Lower Pond, Stream 2, and Associated Wetlands): DDTR were detected in a majority of
sediment samples. Maximum concentrations of 4A-DDD and 4,4'-DDE in sediment were 850,000
Ig/kg and 59,000 Ig/kg, respectively. The maximum concentration of 4,4'-DDT in sediment was
24,000 Ig/kg. Four other pesticides were detected at lower concentrations, including a
maximum of 860 Ig/kg for dieldrin.

• Zone 3 (Upper Pond, Stream 3, Stream 4, and Associated Wetlands): DDTR were detected in all
sediment samples. Maximum concentrations of 4,4-DDD and 4,4'-DDE were 120,000 Ig/kg and
9,000 Ig/kg, respectively. The maximum concentration of 4,4'-DDT was 14,000 Ig/kg. Five
other pesticides were detected at lower concentrations, including a maximum of 900 Ig/kg for
dieldrin. The only notable inorganic detected was lead, at a maximum concentration of
661 mg/kg in a Stream 3 sediment sample.

Zone 4 (North Lake): No DDTR were detected. Certain SVOCs and VOCs were sporadically
detected at low levels. Mercury was detected in one sample.

• Zone 5 (Stream 5): DDTR were detected in all samples. Maximum concentrations of 4A-DDD and
4,4'-DDE were 12,000 Ig/kg and 350 Ig/kg, respectively. The maximum concentration of
4,4'-DDT was 7,000 Ig/kg. Arochlor-1260 was detected in one sample at a concentration of 280
Ig/kg.

-------
              Inorganic concentrations were within an order of magnitude higher than offsite reference
              sample concentrations,  thereby indicating that the level of contamination was not
              significant compared to those of sediment in the streams described previously.

       •       Zone 6 (Stream 6):  DDTR were  detected in one sample out  of two  that were  analyzed for
              pesticides.

             Among pesticides,  4,4'-DDE and 4,4'-DDT were each detected at 120 Ig/kg, and 4,4'-ODD was
             not detected. Inorganic concentrations were within an order of magnitude higher than
             offsite reference sample concentrations, with maximum levels at the outfall of Stream 6.  As
             in Stream 5 sediment, level of inorganic contaminants were not significant compared to
             those of sediment in other streams onsite.

Table 5-1 presents a summary of the soil contamination. Table 5-2 presents a summary of the sediment
contamination. Table 5-3 presents a summary of offsite reference sediment samples for comparison to
site-related sediment contamination.

-------
                                                                                            TABLE 5-1
                                                                               SUMMARY OF SOIL ANALYTICAL RESULTS
                                                                                      AREA A DOWNSTREAM/OBDA
                                                                        NAVAL  SUBMARINE BASE NEW LONDON, GROTON, CONNECTICUT
                                                                                              PAGE 1 OF 4
        Analyte
                                         ZONE
           SURFACE  (<2  FEET)(1)
Frequency    Concentration     Location of
   of            Range          Maximum
Detection                      Detection
      SUBSURFACE  (>2 FEET)(2)
Frequency    Concentration     Location of
   of             Ranqe           Maximum
Detection                       Detection
       SURFACE  (<2 FEET)(3)
Frequency    Concentration
   of            Ranqe
Detection
            ZONE 2
                    SUBSURFACE  (>2  FEET)(4)
Location of    Frequency     Concentration    Location of
  Maximum         of              Ranqe         Maximum
 Detection     Detection                       Detection
1,1-Dichloroethene
2-Butanone
Acetone
Carbon disulfide
Tetrachloroethene
Toluene
Trichloroethene
                                                                                 ND
                                                                                 ND
                                                                                 ND
                                                                                 ND
                                                                                 ND
                                                                                 ND
                                                                                 ND
                                                                                                                             2DMW15S
                                                                                                                                ND
                                                                                                                             2DMW15S
                                                                                                                             2DMW15S
                                                                                                                             2DMW15S
                                                                                                                             2DMW15S
                                                                                                                             2DMW15S
SEMIVOLATILE ORGANICS  (uq/kq)
Benzo(k)fluoranthene
Benzoic acid
Bis(2-Ethylhexyl)phthalate
Fluoranthene
Pyrene
                                                                                 ND
                                                                                 ND
                                                                              2DMW11S
                                                                                 ND
                                                                                 ND
                                                                                 NA
                                                                                 NA
4,4'-ODD
4,4'-DDE
4,4'-DDT
Alpha-Chlordane
Dieldrin
Heptachlor epoxide
                                 MCLL1
                                 MCLL1
                                 MCLL1
                                 2DSS11
                                 2DSS11
                                  ND
Aluminum  (17,600)
Arsenic  (3.6)
Barium  (39)
Beryllium  (0.72)
Cadmium  (0.24)
Calcium  (499)
Chromium  (19.3)
Cobalt  (7)
Copper  (17.9)
                                                            4080-17000
                                                             0.58-2.2
                                                             23.1-31.4
                                                             0.75
                                                              5
                                                              534-865
                                                             6.5-21.9
                                                             6.1
                                                             11.9-12.2
                                 2DMW11S
                                 2DMW11S
                                 2DMW11S
                               2DMW11S
                               2DMW11S
                                 2DMW11S
                                 2DMW11S
                               2DMW11S
                                 2DMW11S
                                  NA
                                  NA
                                                2DMW15S
                                                2DMW15S
                                                2DMW15S
                                              2DMW15S
                                              2DMW15S
                                                2DMW15S
                                                2DMW15S
                                              2DMW15S
                                                2DMW15S

-------
                                                                                            TABLE 5-1
                                                                               SUMMARY OF SOIL ANALYTICAL  RESULTS
                                                                                      AREA A DOWNSTREAM/OBDA
                                                                         NAVAL SUBMARINE BASE NEW LONDON,  GROTON, CONNECTICUT
                                                                                           PAGE 2 OF 4
        Analyte
                                   of
                                Detect!or

INORGANICS  (Background  Maximum Concentration) mg/kg  (continued)

Iron  (16,800)                      1/1          12000
Lead  (17.5)                        1/1           17.8
Magnesium  (2,460)                  1/1           3510
Manganese  (172)                    1/1            255
Nickel  (10)
Potassium  (669)
Sodium  (33)
Vanadium (33.3)
Zinc  (25.6)
 Maximum
Detection
                      SUBSURFACE (>2 FEET) (2
               Freguency     Concentration
                                 Range
Location of
  Maximum
 Detection
7220
15.1
1300
94.
4.4
323
92.
15.
27.
-16100
-28.1
-2880
6-105
-14.3
-1010
2-318
3-31.5
2-82. 1
2DMW11S
2DMW16S
2DMW11S
2DMW16S
2DMW11S
2DMW16S
2DMW11S
2DMW11S
2DMW11S
       SURFACE  (<2  FEET)(3)
Frequency    Concentration
   of            Range
Detection
            ZONE 2
                     SUBSURFACE  (>2  FEET)(4)
Location of    Frequency     Concentration    Location of
  Maximum         of              Ranqe         Maximum
 Detection     Detection                       Detection
                                                                                                                                            2DMW15S
                                                                                                                                            2DMW15S
                                                                                                                                            2DMW15S
                                                                                                                                            2DMW15S
                                                                                                                                            2DMW15S
                                                                                                                                            2DMW15S
                                                                                                                                            2DMW15S
                                                                                                                                            2DMW15S
                                                                                                                                            2DMW15S
                                                                                                           2DMW11S
                                                                                                             2DMW11S
                                                                                                           2DMW16S
                                                                                                           2DMW11S
                                                                                              NA
                                                                                              NA
MISCELLANEOUS PARAMETERS  (mq/kq)

Total orqanic carbon

-------
                                                                                 TABLE 5-1
                                                                      SUMMARY OF SOIL ANALYTICAL RESULTS
                                                                           AREA A DOWNSTREAM/OBDA
                                                            NAVAL  SUBMARINE BASE NEW LONDON, GROTON, CONNECTICUT
                                                                                 PAGE 3 OF 4
        Analyte
                                         ZONE 3
           SURFACE  (<2  FEET)(5)
Frequency    Concentration     Location of
   of            Range          Maximum
      SUBSURFACE  (>2 FEET)
Frequency    Concentration
   of            Ranqe
                                                                                                            Location  of
                                                                                                              Maximum
                                                                                                             Detection
4,4'-DDD
4,4'-DDE
4,4'-DDT
Alpha-Chiordane
Aroclor-1254
Dieldrin
Endosulfan sulfate
Heptachlor epoxide
                                                                                  ND
                                                                                  ND
                                                                                  ND
                                                                                  ND
                                                                                  ND
                                                                                  ND
                                                                                  ND
                                                                                  ND
Aluminum  (17,6
Arsenic  (3.6)
Barium  (39)
Beryllium  (0.7
Cadmium  (0.24)
Calcium  (499)
Chromium  (19.3
Cobalt  (7)
Copper  (17.9)
Iron  (16,800)
Lead  (17.5)
Maqnesium  (2,4
Manqanese  (172
Nickel  (10)
Potassium  (669
Sodium  (33)
Vanadium  (33.3
Zinc  (25.6)
                                                                 1. 8
                                                                 978
                                                                23.6
                                                                 8.3
                                                                22.6
                                                                19800
                                                                 5. 1
                                                                 4420
                                                                 283
                                                                 11.3
                                                                 2340
                                                                 141
                                                                 38.1
                                                                 47.2
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S
                                  2DMW10S

-------
TABLE 5-1
SUMMARY OF SOIL ANALYTICAL RESULTS
AREA A DOWNSTREAM/OBDA
NAVAL SUBMARINE BASE NEW LONDON, GROTON, CONNECTICUT
PAGE 4 OF 4

ZONE 3
SURFACE (<2 FEET)(5) SUBSURFACE (>2 FEET)
Analyte Frequency Concentration Location of Frequency Concentration Location of
of Ranqe Maximum of Ranqe Maximum
Detection

MISCELLANEOUS PARAMETERS
Notes:
1 Includes samples 2DSS11, 3MW12S, and MCLL1.
2 Includes samples 2DMW11S and 2DMW16.
3 Includes samples 2DSS13, 2DSS19 (field duplicate of 2DSS13), 2DSS5, and 2DSS6. Maximum values are used for evaluation of duplicate soil sample
results and are counted as one sample.
4 Includes sample 2DMW15.
5 Includes samples 2DSS1, 2DSS16, and 2DSS2.
6 Includes sample 2DMW10S.
7 ND - Not Detected.
8 NA - Not Analyzed.
9 Values in parentheses represent Federal Toxicity Characteristic Requlatory Level (58 FR 46049)
Backqround maximum concentrations in surface soils were obtained from Table 3-3, Phase II RI (BSR Environmental, March 1997).
"-"implies not applicable if the analyte was not analyzed for or if it was analyzed for but not detected.

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                                                             TABLE 5-2
                                      SUMMARY OF SEDIMENT ANALYTICAL RESULTS  -  ZONES 1 THROUGH 4
                                                      AREA A DOWNSTREAM/OBDA
                                        NAVAL SUBMARINE BASE NEW LONDON,  GROTON,  CONNECTICUT
                                                           PAGE 1 OF 4
                                                ZONE 1(1)
                                              Concentration
                                                  Range
               Frequenc
                                              Location of
                                                Maximum
                                               Detection
                                Frequency
                                    of
                                Detection
                                                              Frequency
                                                                  of
                                                              Detection
2-Butanone
Acetone
Carbon disulfide
Ethylbenzene
Methylene chloride
Tetrachloroethene
Toluene
Trichloroethene
Xylenes, total
 EC-SDS102
 EC-SDOP05
   3SD5
   3SD3
 EC-SDOP05
   3SD5
   3SD4
    ND
   3SD3
                  EC-SDLP11
                  EC-SDLP11
                      ND
                      ND
                      ND
                      ND
                      ND
                      ND
                      ND
                                                   ND
                                                   ND
                                                  2DSD2
                                                   ND
                                                EC-SDUP18
                                                   ND
                                                   ND
                                                 2DSD2
                                                   ND
SEMIVOLATILE ORGANICS  (uq/kq)
2-Nitroaniline                    0/14
4,6-Dinitro-2-methylphenol        0/14
4-Chloro-3-methylphenol           0/14
4-Methylphenol                    2/15
Acenaphthene                      2/15
Anthracene                        2/14
Benzo(a)anthracene                6/15
Benzo(a)pyrene                    4/15
Benzo(b)fluoranthene              4/15
Benzo(q,h,i)perylene              3/15
Benzo(k)fluoranthene              4/15
Benzoic acid                      0/12
Chrysene                          6/15
Di-n-butyl phthalate              1/14
Di-n-octyl phthalate              1/15
Dibenzofuran                      1/14
Fluoranthene                      9/15
Fluorene                          2/14
Indeno(1,2,3-cd)pyrene            3/15
    ND
    ND
    ND
EC-SDOP05
   3SD1
   3SD5
   3SD1
 3SD5
   3SD1
   3SD1
   3SD1
    ND
   3SD5
 EC-SDS102
 EC-SDOP05
   3SD1
   3SD5
   3SD5
   3SD1
    340
140-280
  150-460
  140-290
  170-290
  160-3200
  220-630
    180
     ND
     ND
  EC-SDLP11
  EC-SDLP11
  EC-SDLP11
     ND
  EC-SDLP11
EC-SDLP11
  EC-SDLP11
  EC-SDLP11
  EC-SDLP11
  EC-SDLP11
  EC-SDLP11
  EC-SDS209
     ND
     ND
  EC-SDLP11
     ND
  EC-SDLP11
2DSD2
2DSD2
ND
ND
ND
ND
ND
ND
EC-SDUP18
ND
ND
ND
ND
ND
ND
ND
EC-SDS313
ND
ND
0/4
0/4
0/6
0/4
0/6
0/6
0/6
0/6
1/6
0/6
0/6
0/4
0/6
1/6
0/6
0/4
1/6
0/6
0/6
   ND
   ND
   ND
   ND
   ND
   ND
   ND
 ND
 2DSD10
   ND
   ND
   ND
   ND
NAV90119
   ND
   ND
 2DSD10
   ND
   ND

-------
                                                             TABLE  5-2
                                      SUMMARY OF SEDIMENT ANALYTICAL  RESULTS - ZONES 1 THROUGH 4
                                                      AREA A DOWNSTREAM/OBDA
                                        NAVAL SUBMARINE BASE NEW LONDON,  GROTON,  CONNECTICUT
                                                           PAGE  2 OF  4
                                                ZONE 1(1)
                                              Concentration
                                                  Range
                                                                   3SD1
                                                                    ND
                                                                   3SD5
                                                                   2DSD5
                                ZONE 2(2)
              Frequency     Concentration
                  of            Range
               Detection

                 0/4
                 1/5             310
                 3/6           130-620
                 3/6           190-1000
 Location of
   Maximum
  Detection

     ND
  EC-SDLP11
  EC-SDLP11
  EC-SDLP11
Frequency
    of
Detection
                                    ND
                                    ND
                                    ND
                                 EC-SDUP18
              Frequency
                  of
              Detection
4,4'-ODD
4,4'-DDE
4,4'-DDT
Alpha-Chiordane
Dieldrin
Endosulfan-I
Endrin
Endrin aldehyde
Endrin ketone
Gamma-Chiordane
Heptachlor
  3SD3
  3SD3
EC-SDS103
EC-SDOP06
EC-SDS103
 3DSD4A
   ND
   ND
   ND
EC-SDOP06
EC-SDOP06
  EC-SDLP12
  EC-SDLP12
  EC-SDLP10
     ND
  EC-SOS209
     ND
     ND
  EC-SDS207
  EC-SDLP10
  EC-SDS208
     ND
                                 EC-SDS421
                                  2DSD21
                                 EC-SDS421
                                 EC-SDS421
                                 EC-SDS421
                                     ND
                                 EC-SDUP16
                                     ND
                                     ND
                                 EC-SDUP17
                                 EC-SDUP17
                                                 ND
                                                 ND
                                                 ND
                                                 ND
                                                 ND
                                                 ND
                                                 ND
                                                 ND
                                                 ND
                                                 ND
                                                 ND
                                                                                                                                                               NA
                                                                                                                                                               NA
                                                                                                                                                               NA
Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chromium
  3SD3
   ND
  3SD4
  3SD4
  3SD4
EC-SDOP05
  3SD4
  3SD4
  3SD5
  2DSD25
EC-SDS209
EC-SDS209
EC-SDS209
  2DSD25
EC-SDS209
  2DSD4
EC-SDS209
  2DSD25
            3270-33100
                6. 1
             3.9-17.7
              28-635
             0.51-5.6
              4-23.8
             4.2-13.8
            1290-92200
             9.5-48.9
  2DSD2
EC-SDUP18
EC-SDUP18
EC-SDUP18
EC-SDUP18
EC-SDUP18
  2DSD1
EC-SDS420
  2DSD1
2DSD10
   ND
DN-88118
2DSD10
2DSD10
   ND
2DSD10
2DSD10
2DSD10

-------
                                                              TABLE 5-2
                                      SUMMARY OF SEDIMENT ANALYTICAL RESULTS - ZONES 1 THROUGH 4
                                                      AREA A  DOWNSTREAM/OBDA
                                        NAVAL SUBMARINE BASE  NEW LONDON,  GROTON, CONNECTICUT
                                                           PAGE  3 OF 4
                                                ZONE  1(1)
                                              Concentration
                                                  Range
Frequenc
                               Location of
                                 Maximum
                                Detection
Frequency
    of
Detection
               Frequency
                   of
               Detection
Cobalt
Copper
Cyanide
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Potassium
Selenium
Silver
Sodium
Thallium
Vanadium
Zinc
15/15
15/15
2/13
15/15
15/15
15/15
15/15
1/13
15/15
13/15
10/13
1/13
14/14
0/13
15/15
15/15
3.7-26.6
10.6-118
0.23-3.4
8430-195000
5-223
2170-9640
104-2850
0.33
6. 8-44 .6
534-3620
0.33-3.2
4.3
200-2070
-
15-64.9
18.2-2720
3SD2
3SD2
3SD2
3SD4
3SD2
3SD2
EC-SDS102
3SD1
3SD2
3SD5
3SD4
3SD1
3SD3
ND
3SD4
3SD2
                                EC-SDS209
                                EC-SDS209
                                  2DSD27
                                EC-SDS209
                                EC-SDS209
                                  2DSD25
                                EC-SDS209
                                   ND
                                  2DSD4
                                  2DSD25
                                  2DSD4
                                   ND
                                  2DSD4
                                   ND
                                EC-SDS209
                                EC-SDS209
                5.6-26.7
                18.1-94.3
                0.12-21.4
              18900-639000

                1320-2980
                  129-1300
EC-SDUP18
  2DSD1
EC-SDUP18
EC-SDUP18
EC-SDUP18
  2DSD1
EC-SDUP18
   ND
EC-SDUP18
EC-SDS313
EC-SDUP18
   ND
EC-SDUP18
   ND
EC-SDUP18
  2DSD1
 2DSD10
 2DSD10
    ND
 2DSD10
NAV90119
 2DSD10
 2DSD10
 2DSD31
 2DSD10
 2DSD10
   ND
   ND
 2DSD10
 DN-88118
 2DSD10
 2DSD10
Arsenic  (5.0)
Barium  (100.0)
Cadmium  (1.0)
Chromium  (5.0)
Lead  (5.0)
Mercury  (0.2)
Selenium  (1.0)
Silver  (5.0)

-------
                                                             TABLE 5-2
                                      SUMMARY OF SEDIMENT ANALYTICAL RESULTS  -  ZONES  1  THROUGH 4
                                                      AREA A DOWNSTREAM/OBDA
                                        NAVAL SUBMARINE BASE NEW LONDON, GROTON,  CONNECTICUT
                                                           PAGE 4 OF 4
        Analyte
Frequency
    of
 Detection
MISCELLANEOUS
Ash  (8)
CEC  (meq/100 g)(8)
pH
Specific gravity  (g/cm3)
    Includes samples  112990-3SD1  (0-0.5),  112990-3SD6 (0-0.5)  (field duplicate  of  112990-3SD1 (0-0.5)), 11299D-3DS1  (1-1.5),  112990-3SD2  (0-0.5),  112990-3SD2 (1-1.
    112990-3SD3  (1-1.5),  112990-3SD4  (0-0.5),  112990-3SD4  (1-1.5), 112990-3SD5  (0-0.5),  112990-3SD5 (1-1.5), 120390-2DSD5,  120390-2DSD6  (field duplicate of 120390-
    2DSD29, 3DSD4A, 3SD6,  3SD6  (0-1),  3SD7,  EC-SDOP04-02, EC-SDOP05-02  (4/11/95),  EC-SDOP05-02 (7/19/95),  EC-SDOP06-02, DUP-06  (field  duplicate of EC-SDOPO6-02),
    EC-SDS101-02, EC-SD101-02,  and  EC-SDS103-02.  Maximum values are used  for  evaluation  of sediment sample results and are  counted  as  one  sample.
    Includes samples  120390-2DSD4,  2DSD24,  2DSD25, 2DSD26, 2DS027, 2DSD33  (field duplicate of 2DSD27), EC-SDLP10-2,  EC-SDLP11-2,  EC-SDLP12-2,  EC-SDS207-02, EC-SDS2
    EC-SDS209-02, and DIJP-05  (field duplicate  of EC-SDS209-02). Maximum values  are used  for evaluation of duplicate  sediment  sample  results  and are counted as one
    Includes samples  120390-2DSD1,  120390-2DSD2,  120390-2DSD3,  2DSD18, 2DSD19,  2DSD21, EC-SDS313-02,  EC-SDS314-02, EC-SDS315-02,  EC-SDS419-02,  EC-SDS420-02,
    EC-SDS421-02, EC-SDUP16-02,  EC-SDUP17-02,  and EC-SDUP18-02.
    Includes samples  120390-2DSD10,  2DSD30,  2DSD31, 2DSD32, DN-88118, and  NAV90119.
    ND - Not Detected.
    NA - Not Analyzed.
    Values in parentheses  represent Federal  Toxicity Characteristic Regulatory  Level  (58 FR 46049).
    Cation exchange capacity.

-------
                                                                             TABLE  5-3
                                                             SUMMARY OF  SEDIMENT ANALYTICAL RESULTS
                                                         OFFSITE REFERENCE AREAS FOR AREA A DOWNSTREAM/OBDA
                                                         NAVAL SUBMARINE BASE  NEW  LONDON,  GROTON, CONNECTICUT
                                                                           PAGE 1  OF 2
Sample Number:
Location :
Sample Date:
Ecological Area:
Investigation:
Sample Type:
Status :
EC-SDF828-02
EC-SDFB28
04/08/95
Fishtown Brook
ECO-2
GRAB

EC-SDF829-02
EC-SDFB29
04/08/95
Fishtown Brook
ECO-2
GRAB

EC-SDNP22-2
EC-SDNP22
04/08/95
Niantic Pond
ECO-2
GRAB

                                                                                          Niantic Pond  Niantic Pond
                                                                                          ECO-2         ECO-2
                                                                                          GRAB          GRAB
EC-SDNP24-2
EC-SDNP24
    04/08/95
Niantic Pond
ECO-2
GRAB
EC-SDPP25-02
EC-SDPP25
    04/11/95
      Peguot Woods
ECO-2
GRAB
SEMIVOLATILES  (ug/kg)

4-Methylphenol
4-Nitrophenol
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Benzole acid
Chrysene
Dibenzo(a,h)anthracene
Fluoranthene
Indeno(1,2,3-cd)pyrene
Pentachlorophenol
Phenanthrene
Pyrene
430 U
1000 U
430 U
29 J
430 U
430 U
430 U
1000 U
430 U
430 U
25 J
430 U
1000 U
430 U
23 J
410
6700
2800
170
2800
2800
2800
6700
2800
2800
2800
2800
6700
2800
2800
J
UR
UR
J
UR
UR
UR
U
UR
UR
UR
UR
UR
UR
UR
820 J
7300 UR
190 J
260 J
260 J
170 J
280 J
6600 J
310 J
3000 UR
630 J
190 J
320 J
380 J
530 J
230 J
6700 UR
2800 UR
2800 UR
190 J
2800 UR
160 J
4000 J
190 J
2800 UR
380 J
2800 UR
6700 UR
220 J
290 J
                                           600 J
                                           340 J
                                           480 J
                                           500 J
                                           510 J
                                           430 J
                                           480 J
                                         14000 UR
                                            750 J
                                            160 J
                                           1100 J
                                            320 J
                                            150 J
                                            490 J
                                           1200 J
4,4' -DDD
4,4'-DDE
4,4'-DDT
Alpha-chlordane
Dieldrin
Endrin
Heptachlor

INORGANICS  (mg/kg)
Aluminum
Arsenic
Barium
Beryllium
Boron
Cadmium

-------
                                                                             TABLE 5-3
                                                              SUMMARY OF SEDIMENT ANALYTICAL RESULTS
                                                          OFFSITE REFERENCE AREAS FOR AREA A DOWNSTREAM/OBDA
                                                          NAVAL SUBMARINE BASE NEW LONDON, GROTON,  CONNECTICUT
                                                                            PAGE 2 OF 2
Sample Number:
Location :
Sample Date:
Ecological Area:
Investigation:
Sample Type:
Status :
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Nickel
Potassium
Selenium
Sodium
Vanadium
Zinc
EC-SDF828-02
EC-SDFB28
04/08/95
Fishtown Brook
ECO-2
GRAB

215
3. 1
0. 88
0. 98
1750
3.2 J
417
27. 1 J
1. 8
330 U
1.4 U
51.4 U
4.0
7.7 U
EC-SDFB29-02 EC-SDNP22-2
EC-SDFB29 EC-SDNP22
04/08/95 04/08/95
Fishtown Brook Niantic Pond
ECO-2 ECO-2
GRAB GRAB

11900
13. 6
9 . 6
23. 8
10900
53. 6 J
1290
1240 J
11.4
1910 UR
7.8 ur
297 UR
20.2
97.5
MISCELLANEOUS  PARAMETERS  (mg/kg)

Total Organic  Carbon  (mg/kg)  430                 5973

Notes:
1  Blank indicates  that  the analyte was not analyzed
2  U - Not detected
3  R - Rejected
4  J - Estimated value
                                                                                          Niantic  Pond  Niantic Pond
                                                                                          ECO-2          ECO-2
                                                                                          GRAB           GRAB
3220 J
3. 1 J
1.4 UR
34 .8 J
909 J
309 J
468 J
63.7 J
4 .7 J
953 J
5.5 UR
440 J
5.5 J
35.7 J
6610 J
3.7 J
3.5 J
55.7 J
1520 J
703 J
708 J
118 J
6.9 J
1740 J
8.2 UR
664 J
9.0 J
47.0 J
EC-SDNP24-2
EC-SDNP24
    04/08/95
Niantic Pond
ECO-2
GRAB
EC-SDPP25-02
EC-SDPP25
    04/11/95
      Peguot Woods
ECO-2
GRAB
                                                                                                                                                                      5180  J
                                                                                                                                                                      36.1  J
                                                                                                                                                                      14 .6  J
                                                                                                                                                                      31.0  J
                                                                                                                                                                      33900 J
                                                                                                                                                                        122  J
                                                                                                                                                                      3410  J
                                                                                                                                                                        529  J
                                                                                                                                                                      27.3  J
                                                                                                                                                                      2530  U
                                                                                                                                                                        9.1  J
                                                                                                                                                                      270 UR
                                                                                                                                                                      60.4  J
                                                                                                                                                                        219  J

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                                  6.0 SUMMARY OF SITE RISKS

A baseline risk assessment provides the basis for taking action and indicates the exposure pathways that
need to be addressed by the remedial action. It serves as the baseline indicating what risks could exist
if no action were taken at the site. This section of the ROD reports the results of the baseline risk
assessment conducted for the site.

A Risk Assessment (RA) was performed to estimate the probability and magnitude of potential adverse human
health and environmental effects from exposure to contaminants in various media at the Area A
Downstream/OBDA. The human health risk assessment procedure followed the most recent guidance from the
U.S. EPA  (U.S. EPA,  December 1989 and March 25, 1991) and regional guidance  (U.S. EPA Region I, August
1995, August 1996, and June 1989). The ecological risk assessment procedure followed U.S. EPA  (1992)
guidance to establish the goals, breadth and focus of the assessment. Several widely used sources in
literature were used for the more detailed stages of the ecological risk assessment, as guoted in Section
3.4 of the Phase II RI (B&R Environmental, March 1997).

The human health and ecological risk assessment followed a four step process:  (1) contaminant
identification, which identified those chemicals which, given the specifics of the site, were of
significant concern;  (2)  exposure assessment, which identified actual or potential exposure pathways,
characterized the potentially exposed populations, and determined the extent of possible exposure;  (3)
toxicity assessment, which evaluated the type and magnitude of adverse health and ecological effects due
to exposure to the contaminants; and (4) risk characterization, which integrated the two earlier steps to
summarize the potential and actual non-carcinogenic  (toxic) and carcinogenic (cancer causing) risks posed
by contaminants at the site and uncertainties inherent in the risk assessment process.

6.1     CONTAMINANT IDENTIFICATION

The Area A Downstream/OBDA is one of a number of sites under evaluation at NSB-NLON. Because of the
potential for cumulative risks associated with this site, a single base-wide list of chemicals of concern
was developed. This ensured that chemicals were consistently evaluated from location to location even
though some of the chemicals included on the list may not have been detected at a particular location.
The chemicals evaluated for this area and other sites at NSB-NLON in general are listed below.



Non-carcinogenic PAHs        Carcinogenic PAHs              PCBs
                                                            (Aroclors 1260 and 1254)
Other SVOCs                      Pesticides                     Metals
(12 compounds: primarily     (7 compounds: DDTR, endrin,    (14 elements: Al, Sb, As, Be,
phthalates and phenols       dieldrin,  methoxychlor)        B, Cd, Cu, Fe, Pb,  Mn, Hg, Ni,
                                                            Se, Zn)
BTEX compounds               Chlorinated VOCs               Other VOCs
(All BTEX compounds)         (13 compounds)                 (4 compounds)

Notes:   PAHs:      Polynuclear Aromatic Hydrocarbons
         PCBs:      Polychlorinated Biphenyls
         BTEX:      Benzene, Toluene, Ethylbenzenes and Xylenes
         VOCs:      Volatile Organic Compounds
         SVOCs:     Semi-volatile Organic Compounds

6.2     EXPOSURE ASSESSMENT

Based on information obtained through site visits, inspections, and discussions with personnel at the
Area A Downstream/OBDA or involved in future plans for the area, the following potential receptors were
identified:

       •      Older  child trespassers and recreational users exposed to surface soil up to a depth of 2.0
              feet below surface,  surface water,  and sediment.

       •      Construction workers exposed to all soil to a depth of 10 feet below surface,  sediment and
              groundwater.

       •      Aguatic organisms,  terrestrial vegetation,  soil  invertebrates and terrestrial vertebrates
              exposed to surface soil,  surface water and sediment.

-------
6.3 TOXICITY ASSESSMENT

The toxicity assessment for the contaminants of concern (COCs) examines information concerning the
potential human health and ecological effects of exposure to COCs. The goal of the toxicity assessment is
to provide, for each COG, a quantitative estimate of the relationship between the magnitude and type of
exposure and the severity and probability of human health and ecological effects. Toxicity values are
integrated with the exposure assessment to characterize the potential for the occurrence of adverse
health effects. The toxicological evaluation involves a critical review and interpretation of toxicity
data from epidemiological, clinical, animal, and in vitro studies. This review of the data ideally
determines both the nature of the health effects associated with a particular chemical, and the
probability that a given quantity of a chemical could result in the referenced effect. This analysis
defines the relationship between the dose received and the incidence of an adverse effect for the
chemicals of concern. The entire toxicological data base is used to guide the derivation of cancer slope
factors (CSFs) for carcinogenic effects and Reference Doses (RfDs) for noncarcinogenic effects. These
data may include epidemiological studies, long-term animal bioassays, short-term tests, and comparisons
of molecular structure. Data from these sources are reviewed to determine if a chemical is likely to be
toxic to humans.

The chemicals of concern for ecological receptors are selected based on the finding of chemicals detected
in surface soils, surface water, or sediment or predicted body burdens, in concentrations greater than
regulation-based criteria (such as ambient water quality criteria) , ecological guidance provided by
agencies (U.S. EPA, the Ontario Ministry of the Environment, Oakridge National laboratories, National
Oceanic and Atmospheric Administration, etc.), and supplemental ecological investigations such as benthic
community analyses and sediment toxicity tests. At the Area A Downstream, all of the sources listed above
were used, as quoted in Section 3.4 of the Phase II RI (B&R Environmental, March 1997). As appropriate,
the guidance provided by one or more of these sources was used in developing chemical specific criteria
for the feasibility study.

6.4 RISK CHARACTERIZATION

This section on risk characterization presents the results of the risk assessment from the Phase II RI.
The first part presents a summary of the human health risk characterization. The second part presents a
summary of the ecological risk characterization.

6.4.1 Summary of Human Health Risk Characterization

In order to determine if potentially significant risks exist for human receptors, quantitative estimates
of risk were compared to "acceptable" levels of risk. Estimated His were compared to unity (1.0) .
Estimated ICRs were compared to the U.S. EPA target risk range of 1E-4 to 1E-6 and the Connecticut target
cancer risk of 1E-5.

For Zones 4 through 6, no significant potential human health risks are associated with exposure to
soil/sediment. All estimated His for incidental ingestion of and dermal contact with soil/sediment are
less than 1.0. All estimated ICRs for these exposure routes are within the U.S. EPA target risk range and
less than the Connecticut target risk of 1E-5.

For Zones 1 through 3, potentially significant human health risks (noncarcinogenic and/or carcinogenic)
were calculated for exposure to soil/sediment. For Zone 1, estimated His for the older child trespasser
and construction worker exceeded 1.0 under the Reasonable Maximum Exposure (RME) scenario, where
receptors are assumed to be exposed to maximum detected contaminant concentrations. Elevated risks for
these receptors are primarily attributable to 4.4'-DDT. Estimated His were less than 1.0 for exposure to
soil/sediment at Zones 2 and 3. Although estimated ICRs for all potential human receptors at Zones 1
through 3 are within the U.S. EPA target risk range, estimated ICRs for exposure to soil/sediment under
the RM E scenario exceeded 1E-5 for the construction worker at Zone 1 and the older child trespasser for
Zones 1 through 3. In general, elevated carcinogenic risks for these receptors are associated with
exposure to pesticides (4,4'-DDD, 4,4'-DDT, and dieldrin) and inorganics, (arsenic and beryllium). Table
6-1 presents a summary of the human health risk characterization for Zones 1 through 3. Risks to the
adult recreational user are noted to be at acceptable levels.

A conservative approach to determining the significance of the estimated risks was used by emphasizing
the risks associated with the RME scenario. All estimated His and ICRs for the Central Tendency Exposure
(CTE) scenario, where receptors are assumed to be exposed to average contaminant concentrations, were
less than the target risk levels for noncarcinogenic and carcinogenic effects.

Although the human health risks associated with surface water and groundwater are not addressed in this
ROD, no potential human health risks were calculated for exposure to surface water (i.e., for incidental

-------
ingestion of and dermal contact with surface water, His were less than 1.0 and ICRs were within the U.S.
EPA target risk range or less than the CTDEP limit of 1E-5) . However, His associated with dermal exposure
to groundwater exceeded 1.0 for the construction worker. Elevated potential hazards for this medium are
attributable to antimony and manganese.

Soil and sediment at the site are not considered to be sources of the observed antimony and manganese
contamination in groundwater. Although manganese was detected freguently in the soil/sediment at the
site, the presence of this metal in the groundwater at the Area A Downstream/OBDA site is considered to
be attributable to naturally occurring conditions. Manganese has been widely detected in the groundwater
at concentrations of concern at various sites throughout the Base.

In summary, as shown in Table 6-2, potential human health risks associated with exposure to soil/sediment
at the Area A Downstrearn/OBDA site are attributable to pesticides and inorganics. The older child
trespasser faces a potential health risk exceeding the acceptable limit for cumulative Hazard Index of
1.0. The construction worker faces potential health risks exceeding the acceptable limits of cumulative
Hazard Index of 1.0 and Cumulative Incremental Cancer Risk of 1E-5. Remediation Goals for these chemicals
are presented in Table 6-3. These Remediation Goals are contaminant concentrations that would reduce the
potential health risks to the receptors of concern (i.e., the older child trespasser and construction
workers) to acceptable levels.

6.4.2 Summary of Ecological Risk Characterization

An ecological risk assessment was conducted for the Area A Downstream/OBDA as part of the Phase II RI,
based on samples of surface sails (0-2'), surface water, and sediment. Aguatic organisms (including
benthic organisms), terrestrial vegetation, soil invertebrates, and terrestrial vertebrates were selected
as indicator groups to assess potential impacts to ecological receptors at the Area A Downstream/OBDA.
The following species were used to assess potential risk to terrestrial vertebrates inhabiting this
portion of NSB-NLON:

• Short-tailed shrew
• Barred owl
• Raccoon
• Mallard duck

Table 6-4 summarizes the potential risks to these receptors. Pesticides and to a lesser extent inorganics
pose an unacceptable level of risk to these receptors. Potential risks to ecological receptors can be
estimated using a Hazard Quotient (HQ) or Hazard Index (HI). HQ values provide a measure of the
exceedance of contaminant concentrations compared to thresholds levels for toxicity to organism. An HI
value is a sum of MCI values for each organism considering various contaminants or pathways of exposure.

6.4.2.1 Terrestrial Plants and Invertebrates

DDTR and heptachlor epoxide were identified as likely to cause harm to terrestrial receptors. These
pesticides, being organochlorine in nature, are not known to have herbicidal (i.e., terrestrial plant)
effects. Risks to soil invertebrates exposed to pesticide-contaminated soil were evaluated by estimating
the concentration of each pesticide present in soil moisture and comparing this concentration to
toxicological endpoints protective of these receptors. The results of these comparisons indicated that
DDTR and helotachlor epoxide did not represent a risk to soil invertebrates. Although a soil invertebrate
survey and several earthworm toxicity studies were performed to assess the potential impact of
contaminated soils on soil invertebrates at the Area A Downstream/OBDA, the results of these efforts were
difficult to interpret.

-------
                                 TABLE 6-2

              SUMMARY OF HUMAN HEALTH CHEMICALS OF CONCERNS  (COCs)
                             AREA A DOWNSTREAM/OBDA
              NAVAL SUBMARINE BASE NEW LONDON, GROTON, CONNECTICUT
Zone
                            COCs  (1)
           Noncarcinogenic
               Effects
           4,4'-DDT
           4,4'-DDT

           None  (2)

           None
Carcinogenic Effects

 4,4'-ODD, 4,4'-DDT
 4,4'-ODD, 4,4'-DDT,
 arsenic
 4,4'-ODD, 4,4'-DDT,
 dieldrin, arsenic
 4,4'-ODD, dieldrin,
 arsenic, beryllium
                           Potential Human
                              Receptor
 Construction Worker
Older Child Trespasser

Older Child Trespasser

Older Child Trespasser
      Chemicals associated with a Hazard Index of 1.0 and/or an incremental  cancer  risk  of  1E-6.
      Cumulative Hazard Indices are less than 1.0.

                                             TABLE 6-4

            SUMMARY OF POTENTIAL CHEMICAL-SPECIFIC RISKS TO ECOLOGICAL RECEPTORS OF CONCERN
                                        AREA A DOWNSTREAM/OBDA
                        NAVAL SUBMARINE BASE NEW LONDON, GROTON, CONNECTICUT
Contaminant
ODD
DDE
DDT
Heptachlor epoxide
Dieldrin
Aluminum
Antimony
Arsenic
Barium
Cadmium
Chromium
Cobalt
Copper
Cyanide
Iron
Lead
Manganese
Nickel
Selenium
Vanadium
Zinc
Aguatics HQ
704
110
360


3.9


10.6
1.4

1.1
1.1

3.7
1.2
9.1



2.2
Benthos HQ Mallard HI Raccoon HI
9765.0 29700.0 2.8
4410.0 17503.0
610.1 1326.7

1808.0
1.1 1.2 5.4
45.0
1.7
7.7 1.0
11.8
1.7

3.0
24.3

11.0
1.4
1.9
11.6
2.5
3.0
                                                                                      Shrew HI
                                                                                        31.0
                                                                                        3.7
                                                                                       180.0
                                                                                       170.0
                                                             Owl HI
                                                             1500.0
                                                              180.0
                                                             9000.0
                                                               3.2
Notes:
1     Hazard Quotient  (HQ) or Hazard Index  (HI) based on average concentrations  (not maxima).  Only
      contaminants with an HQ or HI values > 1 are listed. Only HQs or His >  1.0  listed  in  text  tables
      were used to calculate means; if HQs or His for an area were not high enough  to
      be included in tables, zero values were not included in the calculation of  the mean.

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6.4.2.2 Aquatic Organisms

Risks to aquatic organisms were evaluated by taking the ratios (hazard quotients, or HQs) of exposure
concentrations to ambient water quality criteria. Table 6-4 shows that average (across areas) exposure
levels for DDTR and dieldrin result in high potential for ecological risk (as noted by the Hazard
Quotients or HQs and Hazard Indices or His), while common metals have moderate potential ecological risk
and metals like cadmium, lead, and copper have low potential for posing ecological risks.

Macroinvertebrate sediment toxicity tests were conducted for the Phase II RI to determine if sediment
collected from the Area A Downstream/OBDA were toxic. Mortality of test organisms exposed to some
sediment samples collected from Area A Downstrearn/OBDA which is composed of Upper Pond, Lower Pond, OBDA
Pond, and Stream 1-4 was statistically significantly greater than that recorded for organisms exposed to
sediment collected from the reference locations. Survival of two benthic macroinvertebrate species,
Chironomus tentans and Hyalella azteca was extremely low in most sediments and 100% mortality occurred in
Lower Pond sediments. Other physical and chemical characteristics of the sediment (e.g. high
concentrations of organic matter, low dissolved oxygen content and possibly hydrogen sulfide) collected
from these streams and ponds could have contributed to the observed adverse effect. However, these
sediment toxicity test results show that some sediments in the Area A Downstream/OBDA adversely impact
benthic macroinvertebrates.

A triad score method (that used measures of three critical components of ecological effects) was used to
assess the ecological risk. The sediment triad scores were used to compare Area A Downstream/OBDA water
bodies to reference locations in terms of sediment chemistry, toxicity, and macroinvertebrate (e.g.,
aquatic insects, snails, worms) characteristics. Differences between reference and site locations in
toxicity scores are apparent from the sediment triad ranks in Table 6-5.

Chemical data used for a scoring of one of the three components of the triad utilized sediment
concentrations of 18 inorganic (including toxic metals) and 36 organic (including DDTR) analytes. For
each analyte, the concentrations from each water body were scaled so that the values ranged from 1 to
100. The scaling retained proportional relationships of the original data, while providing a standard
scale for all measurements. The standard scale gave each measurement (i.e., concentration for chemicals)
the same weight as other measurements in the final triad summation. The scaled scores were summed to give
the values listed as "Sum Rank Inorganic" and "Sum Rank Organic" for each water body (Table 6-5). These
two values were added together for each water body to yield the "Total Chemical Sum." The "Total Chemical
Sums" for each water body were then scaled from 1 to 100 in the same manner as described above, and the
result listed as "Total Chemical Rank."

The other two components of the triad concerned sediment toxicity and macroinvertebrate community
analysis. Results of sediment toxicity testing and macroinvertebrate community analysis were treated
similarly. However, some date were inverted before scaling in order to make sure that higher values on
every scale indicated worse biological conditions. For example, growth measurements in the FETOX test
were inverted before scaling, so that lower growth rates would come out higher (indicating more toxic
conditions) on the final scale. Scaled responses of test organisms in toxicity experiments (e.g.,
mortality, growth) were summed to yield a "Tox Test Sum" for each water body. Likewise, scaled
measurements of macroinvertebrate community structure (e.g., density, number of species) were summed to
yield a "Taxonomic Sum" for each water body. As with the chemical data, the sums for toxicity and
taxonomy were scaled from 1 to 100, resulting in "Tox Test Rank," and "Taxonomic Rank" scores. The final
step in the triad process was the summing of the "Total Chemical Rank," "Tox Test Rank," and "Taxonomic
Rank" scores for each water body, giving the "Overall Rank." The "Overall Rank" had a potential value of
3 to 300, with higher scares indicating worse biological conditions.

Samples were also collected to characterize the benthic macroinvertebrate community present at the Area A
Downstream/OBDA water bodies. Although macroinvertebrates were present, community parameters (e.g.
population density, community diversity) were generally lower than those calculated for samples collected
from reference locations. Differences between reference and site locations in taxonomic scores are
apparent from the sediment triad ranks in Table 6-5. When coupled with the results of sediment toxicity
tests conducted on samples collected from these same locations, the results of the characterization lend
support to the conclusion that sediments within the Area A Downstream/OBDA represent a significant risk
to benthic macroinvertebrates.

6.4.2.3 Terrestrial Vertebrates

The amount of DDTR to which terrestrial vertebrates may be exposed was determined by calculating the
total dose to these receptors received from ingestion of contaminated prey, incidental ingestion of
soil/sediment, and from drinking water. In the models used to assess risks, barred owls were assumed to

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be exposed to contaminants through the consumption of prey (short-tailed shrews), ingestion of
contaminated water, and through the incidental ingestion of contaminated soil. Short-tailed shrews were
assumed to be exposed through the consumption of contaminated prey (earthworms), consumption of
contaminated water, and the incidental ingestion of soil. Earthworms were assumed to bioaccumulate
directly from contaminated soil. Mallards and raccoons were assumed to be exposed through the ingestion
of contaminated prey (oligochaete worms and frogs, respectively), contaminated water, and the incidental
consumption of sediment. Oligochaetes (benthic macroinvertebrates) were assumed to bioaccumulate
contaminants present in sediment in the same manner as earthworms.

Several conservative assumptions such as assuming home range consisted of the entire site were made on
the input parameters to the food-chain modeling. However, more realistic exposure parameters were
incorporated into the food-chain modeling modified in the Feasibility Study (B&R Environmental, July
1997) . The risk assessment did determine that exposure to contaminated soils represent a potential risk
to terrestrial vertebrates such as the short-tailed shrew, barred owl, mallards, and raccoons. Based on
the modeling results, the potential risks to the terrestrial vertebrates of concern are presented in
Table 6-4.

6.4.2.4 Remediation Goals for Protection of Ecological Receptors

Remediation goals consisting of concentration limits of pesticides and inorganics for protection of
ecological receptors of concern are presented in the following discussion and in Table 6-6. Because of
the differences in the biochemical properties of pesticides and inorganics, the following discussion
presents separate discussions for the derivations of their respective remediation goals.

Pesticides Remediation Goals

Pesticides Remediation Goals for contaminated soil were estimated for food-chain protection (i.e.,
acceptable ERA levels) of terrestrial vertebrates, the selected terrestrial vertebrate species consisted
of the barred owl, the short-tailed shrew, the raccoon and the mallard duck. Allowable soil
concentrations of pesticides for the four selected terrestrial vertebrate species were calculated by
comparing the predicted doses of pesticides from food chain models to species-specific Lowest Observable
Adverse Effects Level (LOAEL) values obtained from literature.

In addition, Pesticide Remediation Goals for sediment were estimated for protection of benthic
macroinvertebrates. Allowable sediment concentration of pesticides for the benthic macroinvertebrates
were evaluated in two ways: 1) by comparing water guality guidelines for DDTR against the potential for
the DDTR present in the sediment to partition into the pore water using eguilibrium partitioning and 2)
by evaluating the relationship between macroinvertebrates community characteristics, sediment toxicity
results and sediment DDTR concentration.

This approach yielded remediation goals of 5.6 mg/kg DDTR for soils and 2 mg/kg DDTR for sediment. These
were selected as the most appropriate remediation goals for all receptors and both media, irrespective of
location on site. Remediation goals for dieldrin were estimated to be in the range of 0.045 mg/kg to
0.195 mg/kg in the sediment. A final remediation goal for dieldrin in sediment will be selected at the
time of remedial design.

Inorganics Remediation Goals

Inorganics, Remediation Goals were selected as National Oceanographic and Atmospheric Administration
(NOAA) Effects Range Median (ER-M) values for the inorganic COCs. Inorganics were identified as
contaminants of concern in sediment and not in soil. By setting ER-M values as remedial goals, the mean
residual concentrations following remediation will be within the range where "occasional" adverse effects
may be expected, which is assumed to be acceptable. ER-Ms are presented in Table 6-6 along with a
range/maximum concentrations for the inorganic contaminants of concern.

Based on the average concentrations exceeding ER-M values, the following COCs are being assigned
corresponding ER-M values as remediation goals:

• Cadmium = 9.6 mg/kg

Lead = 218 mg/kg

Zinc = 410 mg/kg

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6.4.3	Discussion of Uncertainty Factors

Uncertainties in human health risk assessment arise from:

              Selection of COCs

       •      Exposure assessment

       •      Toxicological evaluation

       •      Risk characterization.

Uncertainty in the selection of COCs is associated with the current status of the predictive data bases
and the procedures used to include or exclude constituents as chemicals of concern.

Uncertainty associated with the exposure assessment is associated with the values used as input variables
for a given intake route, the methods used and the assumptions made to determine exposure point
concentrations, and the predictions regarding future land use and population characteristics.

Uncertainty in the toxicity assessment is associated with the guality of the existing data to support
dose response relationships, and the weight-of-evidence used for determining the carcinogenicity of
chemicals of concern.

Uncertainty in risk characterization is associated with exposure to multiple chemicals and the cumulative
uncertainty from combining conservative assumptions made in earlier activities.

While the procedures for human health risk assessment are somewhat standardized and conseguently the
uncertainty factors are controlled, the procedures for ecological risk assessment are less standardized.
The following discussion summarizes these uncertainty factors and states the salient assumptions for
ecological risk assessment  (ERA).

In order to understand how useful or appropriate the results of the ERA are, the uncertainties associated
with the assessment need to be considered. Uncertainties from fairly well-known sources, like errors in
sampling and measurement, will affect the assessment. More serious uncertainties may stem from lesser
known sources, such as how available environmental contaminants are for uptake by exposed plants and
animals, and how well toxicological studies on laboratory subjects relate to organisms in nature. A brief
outline of the uncertainties in the ERA includes:

     Sources of error or variability:

              •      Sampling and measurement
              •      Data handling and analysis

     Incomplete knowledge of the relationship between measured contaminant concentrations and
     actual exposure to contaminants:

              •      Spatial and temporal  factors (e.g.,  lack  of feeding in  areas  of highest  or  lowest
                     contaminant concentrations)
              •      Availability of  contaminants for uptake by organisms
              •      Transfer of contaminants  in food chains

     Incomplete knowledge of toxicology:

              •      Use of non-native organisms and unnatural situations in experiments
              •      Applicability of length of  the  experiment and the  effects  measured
              •      Effects of toxicant mixtures

For the most part, assumptions are made corresponding to uncertainties in the ERA. The following list of
assumptions may help clarify the nature of the uncertainties:

     Sampling and Data Handling

Errors in the design of the sampling program,  performance of sampling,  analytical measurement, data
handling, and data analysis do not have a significant affect on the results of the ERA.  Therefore,
assumptions are not relevant to this aspect of the input.

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     Exposure
       •      Proportion of site size to individual's home range is an adequate exposure factor
       •      Animals are exposed throughout the year
       •      No degradation or loss of contaminants from system
       •      100 percent of each contaminant is available for uptake by organisms
       •      Contaminant transfer from one level of a food chain to the next is adequately described by a
              single factor

     Toxicology
       •      Experimental conditions apply adequately to those at Area A Downstream
       •      Toxicants do not affect each others'  actions via synergistic or antagonistic effects

Uncertainties were reduced and some assumptions avoided through the use of biological data collected in
Area A Downstream. A factor for the transfer of DDTR from soil to soil invertebrates  (earthworms) was
based on field measurements rather than literature values. Also, the sediment RAO for DDTR was based on
an analysis of biological field data, results of sediment toxicity testing, and sediment concentrations
of DDTR. Use of measured responses of native and laboratory animals to site sediment eliminated
uncertainty due to application of toxicity data from literature sources and reduced the uncertainty
associated with exposure assumptions.

6.5      CONCLUSION

Actual or threatened releases of hazardous substances from this site, if not addressed by implementing
the response action selected in this ROD, may present a current or potential threat to public health,
welfare, or the environment.

                            7.0  REMEDIAL ACTION  OBJECTIVES AND DEVELOPMENT OF ALTERNATIVES

This section describes the remedial action objectives and the development of alternatives. Alternatives
are developed for contaminated soil and sediment to meet remedial action objectives for these media.

7.1    STATUTORY REQUIREMENTS/RESPONSE OBJECTIVES

Under its legal authorities, the U.S. Navy's primary responsibility at NPL sites is to undertake remedial
actions that are protective of human health and the environment. In addition, Section 121 of CERCLA
establishes several other statutory requirements and preferences, including: a requirement that the U.S.
Navy's remedial action, when complete, must comply with all federal and more stringent state
environmental standards, requirements, criteria or limitations, under an environmental or facility siting
law unless a waiver is granted; a requirement that the U.S. Navy select a remedial action that is
cost-effective and that utilizes permanent solutions and alternative treatment technologies or resource
recovery technologies to the maximum extent practicable; and a preference for remedies in which treatment
that permanently and significantly reduces the volume, toxicity, or mobility of the hazardous substances
is a principal element over remedies not involving such treatment. Remedial alternatives were developed
to be consistent with these Congressional mandates.

Based on preliminary information relating to types of contaminants, environmental media of concern, and
potential exposure pathways, RAOs were developed to aid in the development of alternatives. These
remedial action objectives were developed to mitigate existing and future potential threats to public
health and the environment. These remedial action objectives are as follows:

       •      Protection of potential human receptors by preventing incidental  ingestion of contaminated
              soil and sediment containing DDT,  ODD,  and dieldrin at concentrations exceeding 27 mg/kg,  38
              mg/kg and 0.57 mg/kg,  respectively.

       •      Protection of potential human receptors by preventing incidental  ingestion of sediment
              containing arsenic and beryllium at concentrations exceeding 6.1  mg/kg and 2.1 mg/kg,
              respectively.

       •      Protection of ecological receptors by preventing contaminated soil (containing DDTR
              concentrations exceeding 5.6 mg/kg rounded down to 5.0 mg/kg, to  be conservative)  and
              contaminated sediment (containing DDTR concentrations exceeding 2.0 mg/kg and dieldrin
              concentrations exceeding 0.045 mg/kg to 0.195 mg/kg)  from entering the food chain.

       •      Protection of ecological receptors from potential toxicity of sediment containing cadmium,
              lead and zinc at concentrations exceeding their respective ER-M values of 9.6 mg/kg,  218
              mg/kg,  and 410 mg/kg.

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ESTIMATED VOLUMES OF CONTAMINATED MEDIA

The most prevalent COG present at concentrations exceeding remediation goals is DDTR. The contaminated
media are the soil and sediment that contain DDTR at concentrations exceeding their respective
remediation goals of 5.0 mg/kg and 2.0 mg/kg of DDTR. These remediation goals are more stringent than
those for protection of human receptors and, therefore, would be protective of both ecological and human
receptors.

Figures 7-1 and 7-2 show the areas of soil and sediment, respectively, that are assumed to contain DDTR
at concentrations exceeding remediation goals. The area of contaminated soil exceeding remediation goals
is estimated to be 2.7 acres, and the area of contaminated sediment exceeding remediation goals is
estimated to be 1.9 acres. Assuming an average depth of contamination of 2.5 feet in soil and ranging
from 2.0 to 2.5 feet (average of 2.3 feet) in sediment, the total volume of contaminated media is
estimated at approximately 18,000 cubic yards, including 11,000 cubic yards of soil and 6,800 cubic yards
of sediment. The estimated volume of sediment containing the inorganic COCs exceeding remediation goals
(i.e., cadmium, lead and zinc) is approximately 5,460 cubic yards within the overall DDTR-contaminated
sediment volume. Because of the relatively low occurrence of dieldrin in the sediment, all of the
dieldrin contaminated sediment containing dieldrin at concentrations exceeding remediation goals are
expected to be within the DDTR and inorganic-contaminated sediment volumes. The definition of the extent
of contamination is very approximate and must be confirmed with additional sampling prior to remedial
action.

7.2 TECHNOLOGY SCREENING AND ALTERNATIVE DEVELOPMENT

CERCIA and the NCP have set forth the process by which remedial actions are evaluated and selected. In
accordance with these reguirements, a list of potential technologies were screened for effectiveness,
implementability, and cost in attaining the remedial action objectives for contaminated soil and
sediment. A range of alternatives were developed from the technologies that were retained from screening.

The FS developed a range of alternatives considering the CERCLA statutory preference for a treatment that
reduces the toxicity, mobility, or volume of the hazardous substances. This range included an alternative
that removes or destroys hazardous substances to the maximum extent feasible, eliminating or minimizing
to the degree possible the need for long-term management. This range also included an alternative that
removes the threat posed by the contaminated media at the site with little or no treatment onsite but
disposes of the material at an offsite facility where the material would be managed in a manner that
would minimize any risk of threat to human health or release to the environment. The range also includes
an alternative that involves little or no treatment onsite but provides protection through engineering or
institutional controls, and a no action alternative.

8.0 DESCRIPTION OF ALTERNATIVES

This section provides a narrative summary of the alternatives that were evaluated in the FS. The
alternatives were as follows: (1) No Action, (2) Capping with Institutional Controls, (3)
Excavation/Dredging of Soil/Sediment, Dewatering, Offsite Disposal, and (4) Excavation/Dredging of
Soil/Sediment, Dewatering, Onsite Thermal Desorption of Soils/Sediment, Onbase Reuse of Treated Soil, and
Offsite Disposal of Sediment.

8.1 ALTERNATIVE 1: NO ACTION

No Action, as the name indicates, is a status-guo alternative. No Action is an alternative that is
reguired to be evaluated under Superfund Law to provide the baseline for comparing the benefits of other
alternatives. This alternative is typically not selected unless the risks of doing nothing are acceptable
to human health and environment.

This alternative would not comply with the following key Applicable or Relevant and Appropriate
Reguirements (ARARs):

• CTDEP Remediation Standard Regulation (criteria developed for direct exposure to potential
receptors would be applicable).

• Executive Order for Protection of Wetlands (applicable because of the presence of wetlands
at the site).

• Coastal Zone Management Act (applicable because the site is present in a coastal area).

-------
Furthermore, this alternative would not comply with the remediation goals. At this site the No Action
alternative would result in contamination being left in place which would be a continued threat to human
health and environment.

8.2 ALTERNATIVE 2: CAPPING, RESTORATION OF WETLANDS AND WATERWAYS, AND INSTITUTIONAL CONTROLS

Capping would consist of the placement of a clean soil cover and a biotic barrier over the contaminated
soils and sediment. All of the groundwater seepage and surface water run on into the, site from the
adjacent Area A wetland and Area A Landfill will be diverted to bypass the areas of proposed capping and
be discharged into downstream culverts. Under this alternative, the standing water in the streams and
ponds (remaining after the groundwater and surface water inflow to the site have been diverted around the
site) would first be pumped, treated by filtration and granular activated carbon (GAG) adsorption at a
wastewater treatment facility to be constructed at a nearby location, and discharged. A permeable layer
of clean soil would be placed over the sediment areas that exceed remediation goals. A layer of gravel
would be placed on top of the clean soil to control erosion of the soil cover. The soil outside of the
ponds and streams would be cleared of vegetation to the extent necessary to provide access to the
underlying contaminated surface soil. The surface soil would then be covered with a layer of clean soil
and a layer of topsoil and revegetated with the native wetland vegetation species of flora. A stainless
steel wire mesh will be placed approximately mid-depth in the cover material to serve as a biotic
barrier. The diversion of surface water and groundwater inflows to the remediated area will be
discontinued and the flow will be re-established through the reconstructed waterways. The function and
value of the wetlands will be replaced according to state and federal standards, as determined during
remedial design. Residues from wastewater treatment (spent filter elements and 10 tons of GAG) would be
disposed of off site.

Institutional controls (fencing and security) would ensure that the soil cover is not disturbed by
trespassers. Monitoring of contaminated media would be conducted to assess any migration or need for
future action. Moreover, in the event of future transfer of property, the deed would carry records of the
contamination and restrict potential land development.

This alternative would comply with the following main location-specific ARARs:

• Executive Order for Protection of Wetlands (applicable because of the presence of wetlands
at the site).

• Federal Clean Water Act, Section 404 (applicable to filling of wetlands).

• Coastal Zone Management Act (applicable because the site is present in a coastal area).

• State of Connecticut Inland Wetlands and Watercourses (applicable to work in wetlands and
watercourses).

The alternative would comply with chemical-specific ARARs and TBCs particularly the State of Connecticut
Remediation Standards for soil.

This alternative would also comply with all action-specific ARARs, key among which are:

• State of Connecticut Water Pollution Control and Water Quality Standards (applicable to
discharge of treated surface water).

• Hazardous Waste Management: Listing and Identification (applicable for testing hazardous
characteristics of DW/WWT residues).

• Hazardous Waste Management: Generator Standards (potentially applicable for handling of
DW/WWT residues).

Estimated Time for Construction: 6 months
Capital Cost: $2,561,000
Operating and Maintenance Cost: $20,000 per year with site review every 5 years ($20,000 per
event) + $50,000 (wetland restoration total cost for years 0 through 5)
Total Cost (as present worth): $2,968,000

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8.3    ALTERNATIVE 3:  EXCAVATION/DREDGING, ONSITE DEWATERING, AND OFFSITE DISPOSAL OF SOIL/SEDIMENT;
       RESTORATION OF WETLANDS AND WATERWAYS; AND MONITORING

Under this alternative, all of the groundwater seepage and surface water run on into the site from the
adjacent Area A Wetland and Area A Landfill will be diverted to bypass the areas of the proposed
excavation and be discharged into downstream culverts. Then, the standing water in the streams and ponds
(remaining after the groundwater and surface water inflow to the site have been diverted around the site)
would be pumped, treated on site by filtration and GAG adsorption at a Dewatering/Wastewater Treatment
(DW/WWT) facility to be constructed at a nearby location and discharged. The contaminated sediment would
then be excavated. The contaminated soil outside of the ponds and streams would be cleared of all
vegetation and excavated. The excavated soil and sediment would be staged separately and transported to
the DW/WWT dewatering facility where these materials would be dewatered in a stockpile. Approximately
23,000 tons of dewatered soil and sediment would be transported off site for disposal. The excavated
areas will be backfilled with clean material and wetlands and waterways reconstructed. The wetlands
functions and values will be restored according to state and federal standards, as determined during
remedial design.

The drainage wastewater from the stockpile would be treated by filtration and GAG adsorption for removal
of TSS and DDTR. The residues from dewatering and wastewater treatment  (600 tons of clogged filter sand,
spent filter elements, and 10 tons GAG)  would be disposed of off site. Depending on the concentration of
DDTR and hazardous characteristics, the dewatered material and wastewater treatment residues would be
disposed of at a nonhazardous waste landfill or a RCRA hazardous waste landfill.

This alternative would comply with the following main location-specific ARARs:

       •      Executive Order for the Protection of Wetlands (applicable because of the presence of
              wetlands at the site).

       •      Federal  Clean Water Act,  Section 404 (applicable to filling of wetlands).

       •      Coastal  Zone Management (applicable because the site is  present in a coastal area).

       •      State of Connecticut Inland Wetlands and Water courses (applicable to work in wetlands and
              water courses).

The removal of contaminated material from the site by excavation and offsite disposal, followed by site
restoration of wetland and waterway functions and values would achieve compliance with the above ARARs.
Furthermore, this alternative would comply with chemical-specific ARARs and TBCs, particularly the State
of Connecticut Remediation Standards for Soil.

This alternative would also comply with all action-specific ARARs, key among which are:

       •      State of Connecticut Water Pollution Control and Water Quality Standards (applicable to
              discharge of treated wastewater).
               Hazardous Waste Management Listing  and  Identification  (applicable for  testing hazardous
characteristics of excavated soil/sediment and DW/WWT residues).

       •      Hazardous Waste Management:  Generator Standards (potentially applicable for excavated
              soil/sediment and DW/WWT residues).

       •      Hazardous Waste Management:  Treatment/Storage/Disposal Facility Standards (potentially
              applicable to the dewatering treatment of soil/sediment  and storage of excavated
              soil/sediment and DW/WWT residues).

Estimated Time for Remedial Action: 12 months
Estimated Cost:                     $8,125,000  (including wetland restoration total  cost for years 0 to 5)

8.4    ALTERNATIVE 4:  EXCAVATION/DREDGING, ONSITE DEWATERING AND THERMAL DESORPTION OF SOIL/SEDIMENT;
       ONBASE REUSE OF TREATED SOIL; OFFSITE DISPOSAL OF SEDIMENT; RESTORATION OF WETLANDS; AND
       MONITORING

Under this alternative, all of the groundwater seepage and surface water run on into the site from the
adjacent Area A Wetland and Area A Landfill will be diverted to bypass the areas of the proposed
excavation and be discharged into downstream culverts. Then, the standing water in the streams and ponds
(remaining after the groundwater and surface water inflow to site have been diverted around the site)
would first be pumped, treated on site by filtration and GAG adsorption, at a DW/WWT facility to be

-------
constructed at a nearby location, and discharged. The contaminated sediment would then be excavated. The
contaminated soil outside of the ponds and streams would be cleared of all vegetation and excavated. The
excavated soil and sediment would be staged separately and transported to the DW/WWT facility where they
would be dewatered in separate stockpiles to produce a total of approximately 23,000 tons of dewatered
material. The excavated areas will be backfilled with clean material and wetlands and waterways
reconstructed. The wetlands functions and values will be restored according to state and federal
standards, as determined during remedial design.

The wastewater would be treated by filtration and GAG adsorption, and discharged. Approximately 11,000
tons of dewatered soil would be treated by thermal desorption for removal of DDTR to meet the soil PRG of
5 mg/kg. The off-gas would be treated and vented to the atmosphere. All of the dewatered sediment would
be disposed of off site at a nonhazardous waste landfill. If a portion of the sediment contain DDTR in
excess of limits deemed acceptable by the nonhazardous waste landfill, it would first be treated onsite
by thermal desorption. None of the sediment can be treated and backfilled on site because inorganic COCs
in the sediment would remain untreated. The treated soil would be reused at a suitable location onbase
above the seasonal high water table elevation. Appropriate reuse locations onbase would be determined
during remedial design. Although the soil would be treated to meet remediation goals for pesticides, it
cannot be backfilled on site. This is because the State's remediation standards reguire attainment of
background levels for organics and inorganic COCs to allow backfilling on site in areas (such as most of
contaminated areas of Area A Downstream/OBDA) that are below the seasonal high water table elevation. The
drainage wastewater from the dewatering stockpiles would be treated by filtration and GAG adsorption for
removal of DDTR. The residues from dewatering, and wastewater treatment (600 tons of clogged filter sand,
spent filter elements, and 20 tons of spent GAG), and offgas treatment (16 tons of spent activated
carbon) would be disposed of off site at a suitable nonhazardous or hazardous waste landfill depending on
their DDTR levels and hazardous characteristics.

This alternative would comply with the following main location-specific ARARs:

• Executive Order for the Protection of Wetlands (applicable because of the presence of
wetlands at the site).

• Federal Clean Water Act, Section 404 (applicable to filling of wetlands).

• Coastal Zone Management (applicable because the site is present in a coastal area).

• State of Connecticut Inland Wetlands and Water courses (applicable to work in wetlands and
water courses).

The removal of contaminated soil and sediment from the site by excavation, treatment with offsite
disposal of sediment and treatment with onbase reuse of soil, followed by restoration of the site's
wetland functions and values would achieve compliance with the above ARARs. Furthermore, this alternative
would comply with chemical-specific ARARs and TBCs, particularly the State of Connecticut Remediation
Standards for soil. This alternative would also comply with all action-specific ARARs, key among which
are:

• State of Connecticut Water Pollution Control and Water Quality Standards (applicable to
discharge of treated DW/WW).

• Hazardous Waste Management: Listing and Identification (applicable for testing hazardous
characteristics of excavated soil/sediment, DW/WWT residues and thermal desorption
residues).

• Hazardous Waste Management: Generator Standards (potentially applicable to excavated
soil/sediment, DW/WWT residues and thermal desorption residues).

• Hazardous Waste Management: Treatment/Storage/Disposal Facility Standards (potentially
applicable to the dewatering treatment of soil/sediment and storage of excavated
soil/sediment and DW/WWT residues).

• Resource Conservation and Recovery Act, Treatment Standards for Hazardous Debris-Thermal
Desorption (applicable for treatment of contaminated soil and sediment onsite although they
are not expected to be hazardous wastes).

• Federal and State of Connecticut Air Pollution Control (applicable to emissions from the
thermal desorber).

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Estimated Time for Remedial Action: 24 months
Capital Cost:                       $9,505,000  (including wetland restoration total  cost for years 0  to 5)

                     9.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES

Section 121(b)(1) of CERCLA presents several factors that, at a minimum, the U.S. Navy is required to
consider in its assessment of alternatives. Building upon these specific statutory mandates, the NCP
articulates nine evaluation criteria to be used in assessing the individual remedial alternatives.

9.1       EVALUATION CRITERIA USED FOR DETAILED ANALYSIS

A detailed analysis was performed on the alternatives using the nine evaluation criteria in order to
select an interim site remedy. Section 9.2 contains a summary of the comparison of each alternative's
strengths and weaknesses with respect to the nine evaluation criteria. These criteria are summarized in
Subsection 9.1.1 through 9.1.3.

9.1.1    Threshold Criteria

The two threshold criteria described below must be met in order for the alternatives to be eligible for
selection in accordance with the NCP.

       •      Overall protection of human health and the environment addresses whether or not a remedy
              provides adequate protection to human health and the environment,  in both the short- and
              long-term,  from unacceptable risks posed by hazardous substances,  pollutants,  or
              contaminants present at the site by eliminating,  reducing or controlling exposure.

       •      Compliance with ARARs addresses whether or not a remedy attains applicable or relevant  and
              appropriate requirements under federal environmental laws and state environmental and
              facility siting laws or provide grounds for invoking a waiver.

9.1.2	Primary Balancing Criteria

The following five criteria are utilized to compare and evaluate the elements of one alternative to
another that meet the threshold criteria.

       •      Long-term effectiveness and permanence addresses the criteria that are utilized to assess
              alternatives for the long-term effectiveness and permanence they afford,  along with the
              degree of certainty that they will prove successful.

       •      Reduction of toxicity,  mobility,  or volume through treatment addresses the degree to which
              alternatives employ recycling or treatment that reduces toxicity,  mobility,  or volume,
              including how treatment is used to address the principal threats posed by the site.

       •      Short-term effectiveness addresses the period of time needed to achieve protection and  any
              adverse impacts on human health and the environment that may be posed during the
              construction and implementation period,  until cleanup goals are achieved.

       •      Implementability addresses the technical and administrative feasibility of a remedy,
              including the availability of materials and services needed to implement a particular
              option.

       •      Cost includes estimated capital costs (indirect and direct)  and annual O&M costs, as well as
              present worth costs.

9.1.3         Modifying Criteria

The modifying criteria are used on the final evaluation of remedial alternatives generally after the U.S.
NAVY has received public comment on the RI/FS and Proposed Plan.

       •      State acceptance addresses the state's position and key concerns related to the preferred
              alternative and other alternatives,  and the state's comments on ARARs and to be considered
              (TBC)  criteria or the proposed use of waivers.

       •      Community acceptance addresses the public's general response to the alternatives described
              in the Proposed Plan and RI/FS report.

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9.2 COMPARATIVE ANALYSIS OF ALTERNATIVES

This section presents a comparison of the remedial alternatives for soil and sediment for Area A
Downstream/OBDA for relative advantages and disadvantages. The criteria for comparison are the same that
were used for the detailed analysis of alternatives. The alternatives being evaluated are as follows:

• Alternative 1: No Action.
• Alternative 2: Capping, Restoration of Wetlands and Waterways, and Institutional Controls.
• Alternative 3: Excavation/Dredging, Onsite Dewatering, and Offsite Disposal of
Soil/Sediment; Restoration of Wetlands and Waterways; and Monitoring.
• Alternative 4: Excavation/Dredging, Onsite Dewatering and Thermal Desorption of
Soil/Sediment; Onbase Reuse of Treated Soil; Offsite Disposal of Sediment;
Restoration of Wetlands; and Monitoring

9.2.1 Overall Protection Of Human Health And Environment

Alternative 1 would not be protective of human health or the environment. Contaminants would remain in
the soil and sediment at concentrations that would exceed remediation goals for both potential human
receptors under the Reasonable Maximum Exposure (RME) scenario and ecological receptors of concern.

Alternative 2 would be protective of human health and environment. The use of a soil cover and
institutional controls would be effective in preventing human trespassers from intrusion into the cover
and for minimizing potential exposure to contaminants. The soil cover and biotic barrier would minimize
the risk of exposure of ecological receptors to the underlying contaminated soil and sediment. The soil
cover over sediment would minimize migration of contaminants to surface water. Restoration of the wetland
and waterways could be more difficult in Alternative 2 than in Alternative 3 and Alternative 4, because
Alternative 2 involves filling the wetlands and waterways above the current wetland elevation.

Alternative 3 would be protective of human health and the environment. The contaminated media would be
removed from the site, followed by disposal by offsite landfilling. Removal of contaminated sediment
would protect surface water from sediment-related contaminants. Clean media would replace the
excavated/dredged soil and sediment, followed by restoration of the wetlands and waterways. The wetland
functions and values will be replaced according to state and federal standards as determined during
remedial design.

Alternative 4 would be protective of human health and the environment. The contaminated soil/sediment
would be removed from the site. Removal of contaminated sediment would protect surface water from
sediment-related contaminants. The soil would be treated by thermal desorption to achieve the remediation
goal of 5 mg/kg DDTR that would reduce the risk of potential receptors to acceptable levels for reuse at
a suitable non-residential location on base. The sediment containing DDTR and inorganic COCs would be
disposed of offsite at a non-hazardous waste landfill with thermal desorption of portions that contain
DDTR exceeding the landfill's limits. Clean media (soil, sand and gravel) would replace the
excavated/dredged soil and sediment, followed by restoration of wetlands and waterways. The wetland
functions and values will be replaced according to state and federal standards as determined during
remedial design.

Alternative 2 is less likely to be protective of the environment than Alternative 3 and Alternative 4
because the contaminated media would be left on site without treatment and long-term maintenance of the
cover would be reguired in the former alternative. Alternative 4 would be the most protective because the
contaminated media are treated prior to disposal/reuse.

Compliance With ARARs And TBCs
Alternative 1 would not comply with the chemical-specific ARARs and TBCs, particularly State of
Connecticut Remediation Standards for Soil. This alternative would not comply with federal/state water
guality criteria. This alternative would not address the Protection of Wetlands as reguired by Executive
Order. Moreover, this alternative would not address the protection of an area within a coastal zone as
reguired by the Coastal Zone Management Act. No action-specific ARARs and TBCs apply to this alternative.

Alternative 2 would comply with chemical-specific ARARs and TBCs, particularly State of Connecticut
Remediation Standards for Soil by minimizing access to the contaminated media if the cap is properly
maintained. This alternative would also comply with federal state water guality criteria and must be
confirmed via monitoring. This alternative would comply with the location specific ARARs associated with
federal and state wetlands protection statutes and Coastal Zone Management if altered wetland functions
and values can be restored. This alternative would comply with ARARs associated with the discharge of
treated water to surface water at the site, mitigation of wetlands and other location-specific ARARs and

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TBCs associated with flood plains and water courses on site.

Alternative 3 would comply with the chemical-specific ARARs and TBCs, particularly State of Connecticut
Remediation Standards for Soil. This alternative would comply with all location-specific ARARs,
particularly regarding wetlands and coastal zone issues. The proposed excavation and removal will also
comply with all action-specific ARARs and TBCs, including protection of waterways, hazardous waste
management, erosion control.

Alternative 4 would also comply with the chemical-specific ARARs and TBCs, particularly State of
Connecticut Remediation Standards for Soil. This alternative would comply with all location-specific
ARARs, particularly regarding wetlands and coastal zone issues. The proposed
excavation/treatment/disposal will also comply with all action-specific ARARs and TBCs, including
protection of waterways, hazardous waste management, erosion control and air pollution control.

9.2.3 Long-Term Effectiveness and Permanence

Alternative 1 would not be effective in the long-term. Residual risks would exceed an HI of 1.0 for
non-carcinogens for the receptors of concern.

Alternative 2 would be effective in the long-term for protection of receptors of concern. Although
contaminants would remain in the soil and sediment, by minimizing access to the contaminants, the risks
would be reduced to His of less than 1.0 for non-carcinogens. However, because long-term monitoring and
maintenance of the cover would be required, this alternative is less effective and less likely to be a
permanent solution than Alternatives 3 and 4.

Alternative 3 would be more effective than Alternative 2 in the long-term for protection of receptors of
concern. The contaminated media would be removed from the site and disposed off site by landfilling.
Although the CERCLA preference for treatment would not be satisfied, disposal in a secure landfill would
be permanent. The risks due to residual contaminants in the soil and sediment on site would be
permanently reduced to His of less than 1.0 for non carcinogens.

Alternative 4 would be the most effective in the long term and would be a permanent remedy. Contaminated
media would be either treated and reused on base or disposed of off site. The risks due to residual
contaminants in the treated soil and remaining soil and sediment on site would be permanently reduced to
His of less than 1.0 for non carcinogens.

9.2.4 Reduction of Toxicitv, Mobility, and Volume Through Treatment

Alternative 1 would offer no reduction of toxicity, mobility or volume. There is no treatment of
contaminated media.

Alternative 2 would offer minimal reduction of toxicity, mobility, and volume through the treatment of
the ponds and streams water prior to placement of the cover.

Alternative 3 would offer minimal reduction of toxicity, mobility through treatment of the ponds and
stream standing water, and dewatering drainage water during remedial action. There would also be some
reduction in volume as a result of soil and sediment dewatering. The contaminated media would merely be
removed from the site and deposited at a more secure offsite location.

Alternative 4 would offer the greatest reduction of toxicity, mobility, and volume through thermal
desorption. Approximately 11,000 cubic yards of soil and portions of highly contaminated sediment
containing a total of 2.8 tons of DDTR, plus a minor amount of dieldrin would be treated to achieve a
minimum of 99 percent removal of DDTR and dieldrin. This would be followed by safe disposal/destruction
of these contaminants captured in approximately 26 tons of solid waste, consisting primarily of spent
GAG. Inorganic COCs in sediment would be deposited off site without treatment. Degree of treatment of
pesticides through thermal desorption would be 100 percent irreversible. Some reduction in volume would
also be achieved through dewatering and minimal toxicity reduction would also result from treatment of
the ponds and stream standing water and dewatering drainage water.

Short-Term Effectiveness
Alternative 1 would have no relevant concerns. There would be no remedial activities under this
alternative.

Alternative 2 would pose significant short-term ecological concerns. Placement of a cover would require
significant disruption of the ecological habitat, because removal of vegetation would be necessary to
access the surface of the contaminated soils. Attainment of remedial action objectives would be expected

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once the remedial action is complete within 4 to 6 months and the disturbed wetland and aquatic habitats
are restored.

Alternative 3 would pose severe short-term ecological concerns. There would be a greater disruption of
the ecological habitat under Alternative 3 than under Alternative 2 because of the excavation/dredging of
all contaminated soil/sediment. Attainment of remedial action objectives would be expected once the
remedial action is complete within 10 to 12 months and the disturbed wetland and aguatic habitats are
restored.

Alternative 4 would also pose the same severe short-term ecological concerns as Alternative 3. The
disruption of habitat under Alternative 4 would be similar to that under Alternative 3. In addition, the
onsite thermal processing of soil/sediment creates a short-term human health concern as a result of
potential worker exposure to contaminants (i.e., soil and offgas emission), although this concern could
be adequately controlled with use of appropriate personal protection equipment (PPE) and offgas
treatment. Attainment of remedial action objectives would be expected once the remedial action is
complete within 16 to 24 months and the disturbed wetland and aquatic habitats are restored.

9.2.6 Implementability

Alternative 1 would be readily implementable. No remedial actions would be involved.

Alternative 2 would be somewhat less easily implementable than Alternative 3, but more easily
implementable than Alternative 4. The remedial activity would involve the use of relatively simple
technologies and would be the least dependent on the availability of offsite disposal facilities. There
are potential difficulties in restoring lost wetland functions and values within the filled, capped
wetlands. The difficulties in restoring the wetland functions and values can be adequately addressed by
proper choice of soil cover material that would be suitable for wetland plant growth.

Alternative 3 would be more easily implementable than Alternative 4. Alternative 3 and Alternative 4
would involve a potentially more site restoration (because of excavation/dredging and backfilling) and
greater use of offsite disposal of wastes than Alternative 2. Any additional remediation could be more
easily implemented under Alternatives 1, 3 or 4 than under Alternative 2.

Alternative 4 would be the least easily implementable alternative. Alternative 4 would involve the onsite
mobilization and operation of a treatment unit, that requires specialized personnel and trained
operators. This technology is offered by a relatively few number of contractors. Moreover, Alternative 4
would require coordination with state agencies to negotiate discharge limits for not only treated
wastewater discharge to onsite surface waters, but also for treated off gas discharge. However,
Alternative 4 would involve less dependence on the availability of offsite disposal facilities because
the treated soil would be reused at the base.

Any additional remedial action could be more readily undertaken under Alternatives 3 and 4 than under
Alternative 2 because of the presence of a cap under Alternative 2. However, additional remedial actions
would be implementable following any of these alternatives.

9.2.7 Cost

Capital, annual operation/maintenance and net present worth costs of alternatives are compared here.
Present worth costs are estimated only if the duration of the remedial action is prolonged such as the
long-term monitoring and maintenance involved in Alternative 2.

Alternative 1:
Capital Cost: $ 0
• Operation/Maintenance Cost: $ 0
Net Present Worth: $ 0
Alternative 2:
Capital Cost: $2,561,000
Operation/Maintenance Cost: $ 20,000/yr + $ 20,000/5 yr + $50,000 (wetland restoration
total cost for years 0 to 5)
Net Present Worth: $2,968,000

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Alternative 3:
              Capital Cost:  $8,080,000
              Operation/Maintenance Cost:  $50,000 (wetland restoration total cost for years 0 to 5)
              Net Present Worth:  $8,125,000
Alternative 4:

              Capital Cost:  $9,460,000
       •      Operation/Maintenance Cost:  $50,000 (wetland restoration total cost for years 0 to 5)
              Net Present Worth:  $9,505,000

9.2.8         State Acceptance

The CTDEP, as a party of the FFA, has provided comments on the FS and Proposed Plan, and has documented
its concurrence with the remedial action,  as stated in Section 13 of this ROD. A copy of the CTDEP's
letter of concurrence is presented in Appendix C of this ROD.

              Community Acceptance
The Proposed Plan presents the preferred alternative for Area A Downstream/OBDA. From August 1, 1997
through September 1, 1997, the U.S. Navy held a public comment period to accept public input. A public
meeting was held on August 6, 1997 to discuss the Proposed Plan and to accept any oral comments.

Community acceptance of the Proposed Plan was evaluated based on comments received at the public meeting
as documented in the transcript of the Public Meeting in Appendix A. No comments were received from the
public during the public comment period.

                                    10.0 THE SEIiECTED REMEDY

Based upon consideration of reguirements of CERCLA, the NCP, the detailed analysis of alternatives, and
U.S. EPA, state, and public comments, the Navy has selected Alternative 3 (Excavation/Dredging, Onsite
Dewatering, and Offsite Disposal of Soil/Sediment; Restoration of Wetlands and Waterways; and Monitoring)
as the most appropriate remedy for soil and sediment at Area A Downstream/OBDA at NSB-NLON. At the
completion of this remedy, the risk associated with soil and sediment at this site will be protective of
human health and the environment.

The selected remedy consists of excavation of the contaminated soil and sediment, followed by onsite
dewatering and offsite disposal. The seguence of actions envisioned at a conceptual state is as follows:
(1) removal, onsite treatment, and discharge of standing water from ponds and streams with appropriate
stream flow diversions; (2) clearing/grubbing of contaminated soil areas; (3) dredging, onsite dewatering
and offsite disposal of contaminated sediment;  (4) excavation, onsite dewatering and offsite disposal of
contaminated soil;  (5)  placement of clean soil backfill over the excavated soil areas with top soil cover
and revegetation to replace altered wetland functions and values; and (6) placement of suitable borrow
material over the dredged sediment areas (such as sand in ponds and gravel in streams) and restoration of
aguatic habitats. Fencing and security measures are assumed to be present and will continue to be
instituted during the remedial action. Figure 10-1 presents the conceptual remediation plan for
Alternative 3.

Approximately 1.0 million gallons of standing water will be treated on site at the Dewatering/Wastewater
Treatment  (DW/WWT) facility and discharged downstream of the site at a suitable location in a storm sewer
that will ultimately discharge to Thames River. Approximately 7,000 cubic yards of contaminated sediment
(an estimated area of 1.9 acres down to an average depth of 2.3 feet) will be excavated. The estimated
depths of excavation are expected to vary between 0.5 feet to 3.0 feet depending on the depth to clean
sediment. The excavated sediment will be transported to the DW/WWT facility. This facility is expected to
be constructed at a suitable location at or near the neighboring Area A Landfill. Furthermore,
approximately 11,000 cubic yards of contaminated soil (within an estimated area of 2.7 acres, down to an
assumed depth of 2.5 feet) will be excavated and transported to the DW/WWT facility. The areas, depths
and volumes of excavation are likely to change when the extent of contamination is clearly defined at the
time of remedial design.



Prior to excavation at the OBDA, during the remedial design phase, the stability of the northwest side
slope of the adjacent Area A Landfill will be evaluated. At that time, appropriate measures will be
taken, if necessary, to minimize any adverse effects that could result from excavation.

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The DW/WWT facility will consist of separate dewatering pads for sediment and soil, a bag filtration unit
and a GAG adsorption unit. The dewatering pad will be a layered structure consisting of sand, gravel, and
an impermeable base. The sand layer will be sandwiched between geotextile/geonet layers. The pad will be
bermed and provided with an underdrain and sump. Each pad will provide a total of approximately 1,620
sguare feet of stockpiling area and will be designed to accommodate approximately 300 cubic yards of
soil/sediment assuming an average stockpile height of 5 feet. The soil/sediment will be stockpiled on the
top geotextile layer and covered with an impervious synthetic liner to prevent potential rainfall
infiltration. A suitable weight (such as concrete slabs) will be placed on top of the pile to promote
dewatering. The top liner is also expected to prevent the weight from becoming embedded in the pile. The
cross section of the dewatering pads will consist of the following components in descending order as
depicted in Figure 10-2:

• A graded sand layer: 1.0 foot in thickness, sandwiched between two geotextile/geonet
membranes.

• A gravel layer: 1.0 foot in thickness.

• A High Density Poly Ethylene (HDPE) liner on compacted and sloped soil base.

• A slotted PVC pipe: 4 inches in diameter, placed within the gravel layer, along the entire
deep end of the base.

The sand and geotextile/geonet layers in the base of the pad are expected to function as a preliminary
filter to retain gross TSS and most of the soil particles, while allowing relatively solids-free drainage
water into the gravel underdrain layer. The slotted PVC pipe in the gravel layer will collect drainage
water and transfer it to an adjacent sump. Drainage water will then be pumped into a bag filtration unit
for secondary TSS removal, followed by GAG adsorption for removal of dissolved DDTR. The treated drainage
water will then be discharged using a pump via a pipeline leading to a suitable storm sewer downstream of
Area A Downstream/OBDA that will eventually discharge to the Thames River.

Standing water that will be pumped from the ponds and streams prior to dredging as well as drainage from
the dewatering stockpile will undergo preliminary filtration in the dewatering pad drainage layers
followed by bag filtration and GAG adsorption. It is anticipated that the standing water will contain, on
average, less than 30 mg/L of TSS and less than 1 Ig/L of DDTR which would meet the anticipated discharge
limits. Therefore, treatment is a conservative measure prior to discharge to the Thames River. However,
the drainage water from the dewatering stockpile is expected to be significantly more contaminated,
containing up to 2.2 mg/L of DDTR (in particulates of 0.45 Im size and larger) and up to 2,000 mg/L of
TSS, based on information obtained during a bench-scale dewatering study on sediment (Atlantic, May
1994). The preliminary filtration in the dewatering bed is assumed to reduce the TSS from approximately
2,000 mg/L to approximately 100 mg/L. Bag filtration will reduce the TSS further to 5 mg/L as
pretreatment for GAG adsorption. GAG adsorption will remove the DDTR to achieve less than detection
limits (1 Ig/L) in the treated effluent. The effluent will be periodically monitored in accordance with
substantive reguirements of Connecticut State's discharge permit.

Each dewatering bed will be capable of accommodating a flow of 200 gpm from the discharge of standing
water from the water bodies. The hydraulic flux corresponding to this flow rate will be less than 0.5
gpm/ft 2 and, therefore, will be easily accommodated. However, this flow rate of 200 gpm must be
distributed uniformly over, the surface of the dewatering bed to prevent any channeling effect that could
disrupt the bed and reduce filtration efficiency. If analysis of the standing water shows minimal TSS
levels (i.e., less than 15 mg/L), then it will be discharged directly into the dewatering bed sump for
treatment by bag filtration and GAG adsorption.

Drainage water from the stockpile will be treated at a rate of less than 10 gpm in the dewatering bed.
The sand filtration layer is assumed to reguire replacement when the solids accumulated within it reaches
a limit of 1.0 Ib/ft 2 (dry basis). At that time, the sand and geotextile layers will be removed, tested
to determine if hazardous; disposed of off site and replaced with clean layers. The sand/geotextile media
is estimated to reguire replacement approximately 7 times, based on an estimated wastewater volume
720,000 gallons, conservatively assumed to contain 2,000 mg/L of TSS, If a portion of the sand/geotextile
media contains concentrations of COCs at levels not acceptable at a nonhazardous waste landfill, it will
be disposed of at a RCRA hazardous waste landfill.

Prior to excavation, the existing vegetation in the contaminated soil areas will be cleared and the roots
grubbed. The extent of clearing, grubbing, and excavation will be limited strictly to the areas of
contaminated soil in order to minimize habitat destruction. Approximately 11,000 cubic yards of soil and
6,800 cubic yards of sediment will be excavated; dewatered on site to yield a total waste mass of 20,300

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tons; and disposed of at a nonhazardous waste landfill. If a portion of the sediment contain
concentrations of DDTR or other COCs at levels not acceptable at a nonhazardous waste landfill, it will
be disposed of at a RCRA hazardous waste landfill. The contaminated sediment that will be disposed of
offsite will also contain minor amounts of dieldrin. Within the total excavated sediment volume of 6,800
cubic yards, approximately 5,680 cubic yards will also contain inorganic COCs (Cd, Zn, and Pb) in excess
of remediation goals which will reguire offsite disposal regardless of DDTR concentrations.

Following excavation of contaminated soil, approximately 11,000 cubic yards of clean borrow fill material
including 2,200 cubic yards of top soil will be spread and revegetated with suitable wetland species of
flora. In wetland areas where canopy loss would be inevitable, trees of the same species, i.e., Red Maple
(Acer rubrum) or Black Gum (Nyssa sylvatica) will be replanted. The wetland functions and values will be
replaced according to state and federal standards, as determined during remedial design. Following
excavation of contaminated sediment, approximately 4,900 cubic yards of suitable borrow material will be
backfilled in the streams and ponds to maintain the original contour of the water bodies. Suitable borrow
materials for ponds and streams are assumed to be sand and gravel, respectively. Sand is expected to be
similar to the existing sediment in the ponds. Moreover, the streams are man-made with hard substrate.
Gravel, as opposed to sand is expected to be more suitable in streams where the flow of water (and hence
the potential for erosion) is greater than the ponds. The volume of clean material used to backfill the
excavated areas of ponds and streams will be eguivalent to the excavated sediment; and the excavated
sediment and wetland functions and values of the waterways will be replaced according to state and
federal standards, as determined during remedial design. At the time of remedial design, alternative
methods of erosion control such as placement of hay bales or high velocity matting might be considered if
determined to be more compatible with the natural habitat.

Table 10-1 presents a summary of the remediation goals for each contaminant of concern in soil and
sediment that would be protective of both human and ecological receptors of concern. These remediation
goals were derived for protection of ecological receptors of concern and are sufficiently low to be
protective of human receptors of concern. Additional sampling and analysis for DDTR, dieldrin, and
inorganic COCs would be reguired at the time of remedial design to verify the area and depth of
contamination exceeding these remediation goals. At that time, the volumes of contaminated media, the
process details, and logistics would be more accurately estimated.

The cost associated with this selected remedy is estimated to be $8,125,000 with an accuracy of +50 to
-30 percent. The cost includes a component of $1,263,000 associated with contingency, eguivalent to 20
percent of the total field cost.

TABLE 10-1
SUMMARY OF REMEDIATION GOALS PROTECTIVE OF
HUMAN AND ECOLOGICAL RECEPTORS OF CONCERN
AREA A DOWNSTREAM/OBDA
NSB-NLON GROTON, CONNECTICUT

Contaminant of Medium of Concern
Concern Soil Sediment
DDTR 5.0 mg/kg 2.0 mg/kg
Dieldrin Not a COG 0.045 mg/kg
Cadmium Not a COG 9.6 mg/kg
Lead Not a COG 218 mg/kg
Zinc Not a COG 410 mg/kg

11.0 STATUTORY DETERMINATIONS

The remedial action selected for Area A Downstream/OBDA is consistent with CERCLA and the NCP, to the
extent practicable. The remedial action is protective of human health and the environment, complies with
ARARs, and is cost effective. The remedial action does not satisfy the statutory preference for remedies
that reduce contaminant toxicity, mobility and volume through treatment as a principal element. However,
the remedial action removes the significant potential threat of the contaminants at the site, followed by
safe management at an offsite disposal facility.

11.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT

The selected remedial action will be protective of human health and the environment at the site by
removing the contaminated material, thereby significantly reducing the health risks to potential human
and ecological receptors. The soil and sediment that contain contaminants of concern at levels higher

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than the acceptable limits corresponding to a cumulative ICR of IE-OS and cumulative non-carcinogenic HI
of 1.0 will be removed from the site. Although significant destruction of habitat will occur because of
the removal of vegetation and excavation, the benefits of contaminant removal will outweigh the
short-term effects following restoration of the site and recovery of the functions and values of the
wetlands in the long term. The contaminated media will be disposed of in approved and permitted
nonhazardous and hazardous waste landfills where they will be managed appropriately to minimize exposures
to human health and the environment off site.

11.2 COMPLIANCE WITH ARARs

The selected remedial action will comply with federal and State of Connecticut ARARs. The ARARs and TBCs
that have been analyzed for this remedial action and the methods that will be employed to achieve
compliance with the ARARs and TBCs are summarized in Table 11-1, 11-2, and 11-3.

11.3 COST-EFFECTIVENESS

In the U.S. Navy's judgment, the selected remedy is cost effective, i.e., its overall protectiveness
justifies the cost. In selecting this alternative, the Navy analyzed the overall effectiveness of all
alternatives that were protective of human health and environment and complied with ARARs. The overall
effectiveness of the alternatives were assessed by considering a combination of three relevant criteria;
(1) long-term effectiveness and permanence, (2) reduction of toxicity, mobility and volume through
treatment as a principal element, and (3) short-term effectiveness.

The No Action alternative is the least expensive (zero cost) alternative, but it would not be protective
of human health and the environment. Therefore, only three other alternatives were analyzed further for
overall effectiveness with respect to cost. Capping is the least expensive among the three alternatives,
but it is guestionable in its long-term effectiveness and permanence because it would allow the
contaminants to remain on site and potentially migrate if the cover is not maintained, and would not
employ treatment as a principal element. Therefore, although capping would be the most short-term
effective alternative, it is not favored. Excavation and onsite treatment by thermal desorption is the
only alternative that would be effective in the long-term and permanent and that would also reduce
contaminant toxicity using treatment as the principal element. This alternative is the most expensive,
and, there would be considerable short-term effectiveness concerns because of temporary ecological
habitat destruction. Moreover, thermal desorption treatment on site would also pose potential hazards to
worker health and the nearby community. Excavation with off site landfill disposal is less expensive than
the onsite treatment alternative, and it will be effective in the long term because the contaminants will
be removed from the site for safe management offsite. Although there will be considerable short-term
effectiveness concerns also associated with this alternative because of temporary ecological habitat
destruction, the costs using offsite landfill disposal rather than onsite thermal desorption are
considered more justified for the long term benefits of removing contaminants from the site.

Estimated Cost of selected remedial alternative: $8,125,000

-------
TABIiE 11-1

CHEMICAL-SPECIFIC ARARs AND TBCs
ALTERNATIVE 3 - EXCAVATION/DREDGING, ONSITE DEWATERING, AND
OFFSITE DISPOSAL OF SOIL/SEDIMENT; RESTORATION OF
WETLANDS AND WATERWAYS; AND MONITORING
AREA A DOWNSTREAM/OBDA
NSB-NLON GROTON, CONNECTICUT
PAGE 1 OF 2
FEDERAL
Requirement

Water Quality Criteria for DDT and
Metabolite (EPA 440-80-038), 1980
Citation Status

TBC
Technical Basis for deriving Sediment
Quality Criteria for Non-Ionic Organic
Contaminants for Protection of
Benthic organisms by Using
Equilibrium Partitioning (EPA-822-R-
93-011).1993
National Oceanographic and
Atmospheric Administration (NOAA)
Incidence of Adverse Biological
Effects within Ranges of Chemical
Concentration in Marine and
Estuarine Sediments (Long et. al. ,
1995)
Cancer Slope Factors (CSF).
Reference Dose (RfD)
TBC
Synopsis of Requirement

Provides criteria for assessing toxicity of DDT and
metabolics to aquatic organisms.
Guidance for estimating cleanup goals for
sediment contamination.
TBC
TBC
TBC
Guidance on concentration ranges of
contaminants in sediment that would rarely or
more likely to have adverse effects. Findings
comparable with fresh-water sediments.
These are guidance values used to evaluate the
potential carcinogenic or non-carcinogenic hazard
caused by exposure to contaminants.

These are guidance values used to evaluate the
potential carcinogenic or non-carcinogenic hazard
caused by exposure to contaminants.
Action to Be Taken to Attain ARAR

DDTR contaminated soil/sediment would be
excavated, removed, and replaced with
uncontaminated material. Remaining
soil/sediment would provide no source of
contamination to surface waters and would pose
no hazard to potential aquatic receptors.
Contaminated sediment would be excavated,
removed, and replaced with uncontaminated
material. Remaining sediment would pose no
hazard to potential receptors. Removal of
contaminated sediment would achieve protection
of receptors of concern.
Contaminated sediment would be excavated,
removed, and replaced with uncontaminated
material. Remaining sediment would pose no
hazard to potential receptors. Removal of
contaminated sediment would achieve protection
of receptors of concern.

Contaminated soil/sediment would be excavated,
removed, and replaced with uncontaminated
material. Remaining soil/sediment would pose no
hazard to potential receptors.
Contaminated soil/sediment would be excavated,
removed, and replaced with uncontaminated
material. Remaining soil/sediment would pose no
hazard to potential receptors.

-------
                                                  TABIiE 11-1

                                        CHEMICAL-SPECIFIC ARARs AND TBCs
                         ALTERNATIVE 3 - EXCAVATION/DREDGING, ONSITE DEWATERING, AND
                             OFFSITE DISPOSAL OF SOIL/SEDIMENT; RESTORATION OF
                                   WETLANDS AND WATERWAYS; AND MONITORING
                                            AREA A DOWNSTREAM/OBDA
                                         NSB-NLON GROTON, CONNECTICUT
                                                  PAGE 2 OF 2

STATE OF CONNECTICUT

           Requirement              Citation      Status             Synopsis of Requirement                           Action  to  Be  Taken  to Attain ARAR

Soil Remediation Standards    RCSA ° 22a-133k-  Applicable    Requlations specify remediation standards for     Direct exposure would be prevented by removinq
                              1 thru 2                        direct exposure to soil and sediments.            the  contaminated  soil/sediments  from  the site
                                                              Requlations also specify qroundwater protection   followed by  safe  disposal  offsite.  Standards for
                                                              standards for contaminated soil in areas with a   soil remediation  within a  GB qroundwater zone
                                                              state qroundwater classification of GB.           are  applicable.

-------
                                                                     TABLE  11-2
                                                        LOCATION-SPECIFIC ARARs AND  TBCs
                                        ALTERNATIVE  3 - EXCAVATION/DREDGING,  ONSITE DEWATERING,  AND
                                                OFFSITE DISPOSAL OF  SOIL/SEDIMENT;  RESTORATION  OF
                                                       WETLANDS AND WATERWAYS;  AND MONITORING
                                                                AREA A  DOWNSTREAM/OBDA
                                                             NSB-NLON GROTON, CONNECTICUT
                                                                      PAGE  1 OF  2
Clean Water Act, Section 404
                                                                              Applicable
                                                                              Applicable
                                   16 USC Part
                                   122.49
                                                 61  et.  seq.,  4 0  CFR
                                                                              Applicable
                                                                                             These rules regulate the discharge of dredge
                                                                                             and fill materials in wetlands and navigable
                                                                                             waters.  Such discharges are not  allowed  if
                                                                                             practicable alternatives are available.
                                                                                             This Order requires Federal agencies to  take
                                                                                             action to avoid adversely impacting
                                                                                             wetlands wherever possible, to minimize
                                                                                             wetlands destruction and to preserve the
                                                                                             values of wetlands, and to prescribe
                                                                                             procedures to implement the policies and
                                                                                             procedures of this Executive Order.
This order protects fish and wildlife when
Federal actions result in control  or structural
modification of a natural stream or body  of
water.
Remedial action includes dredging  of  soil  and
sediment from the contaminated wetlands  and
replacement/restoration with uncontaminated
material.  Measures would be taken  to
minimize adverse effects and to replace  or
restore protected wetland functions and
values.
Remedial action includes dredging  of  soil  and
sediment from the contaminated wetlands  and
replacement/restoration with uncontaminated
material.  However, measures to minimize
adverse effects and to replace or  restore
protected wetland functions and values would
be considered and incorporated into any  plan
or action wherever feasible.

Appropriate agencies would be consulted  prior
to implementation to find ways to  minimize
adverse effects to fish and wildlife  from
excavating and restoring the contaminated
wetlands and waterways.
                                                                              Applicable
                                                   Portions  of the site are located in a coastal
                                                   zone  management area;  therefore, applicable
                                                   coastal  zone management requirements need
                                                   to  be addressed.
This order requires Federal agencies to            Although  the 100-year  floodplain for the
evaluate the potential effects of  actions  it  may   Thames River only include Streams 5 and 6
take within a designated 100-year  floodplain       for which no action is proposed, this order
of a waterway to avoid adversely impacting        may be applicable to the streams on site,
floodplains whenever possible.                     which may be classified as inland waters.
                                                   Measures  would be taken to minimize impacts
                                                   during excavation and  backfilling

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                                                                          TABLE 11-2

                                                    LOCATION-SPECIFIC ARARs AND TBCs
                                   ALTERNATIVE  3 -  EXCAVATION/DREDGING,  ONSITE  DEWATERING,  AND
                                         OFFSITE DISPOSAL OF  SOIL/SEDIMENT;  RESTORATION OF
                                               WETLANDS AND WATERWAYS; AND MONITORING
                                                         AREA A  DOWNSTREAM/OBDA
                                                     NSB-NLON GROTON,  CONNECTICUT
                                                               PAGE 2  OF 2
STATE OF CONNECTICUT
CT Endangered Species Act CGS ° 26-303 thru  314
                                                                                                                          This  alternative  proposes  to dredge soil and
                                                                                                                          sediment  from  the contaminated wetlands and
                                                                                                                          watercourses and  to  restore  the areas using
                                                                                                                          uncontaminated material.  The substantive
                                                                                                                          reguirements of the  CT  standards would be met
                                                                                                                          to address  the alteration  of wetlands and
                                                                                                                          watercourses.
                                                                                                                 coastal  This  alternative  proposes  to dredge contaminated
zone consistency determination under these
rules,  which includes the goal that
development, preservation, or use  of land and
water resources of a coastal area  proceed
without significantly disrupting the natural
environment.
Regulates activities affecting state-listed
endangered or threatened species or their
critical habitat.
soil and sediment from areas within the  coastal
zone and to restore the areas using
uncontaminated material. The substantive
reguirements of the CT standards would be met
to address the alteration of the coastal zone.

Two state-threatened plants, Golden Alexanders
and Seaside Crowfoot, have  been sighted  in  the
NSB-NLON area.  In addition, three  state  special
concern species, Creeping Bush-clover,
Crooked-stem Aster, and Carex crawfordii, have
been documented in the NSB-NLON area.
Excavation and restoration  of the  contaminated
area would be implemented so as to address
potential negative impacts  to the  listed plant
species or any of their critical habitat which
might occur within the site.

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                                                                     TABLE  11-3

                                                         ACTION-SPECIFIC  ARARs  AMD  TBCs
                                       ALTERNATIVE  3 - EXCAVATION/DREDGING,  ONSITE DEWATERING,  AND
                                                         OFFSITE  DISPOSAL OF SOIL/SEDIMENT;
                                           RESTORATION OF  WETLANDS  AND  WATERWAYS;  AND  MONITORING
                                                               AREA A  DOWNSTREAM/OBDA
                                                          NSB-NLON GROTON,  CONNECTICUT
                                                                     PAGE 1 OF 2
     Requirement

Clean Water Act, Section
402, National Pollution
Discharge Elimination
System  (NPDES)

STATE OF CONNECTICUT

Water Pollution Control
                                                            Applicable
Hazardous Waste
Management:   Generator
and Handler Requirements,
Listing and Identification
                                 RCSA  22a-449(c)  100-101     Applicable
                                                                           Connecticut's Water Quality Standards  establish
                                                                           specific numeric criteria, designated  uses,  and
                                                                           anti-degradation policies for groundwater  and
                                                                           surface water.
CT is delegated to administrate the  federal  RCRA
statute through its state regulations.  These
sections establish standards for listing  and
identification of hazardous waste. The  standards
of 40 CFR 260-261 are incorporated by reference.
                                                    Surface  water removed prior to dredging, along
                                                    with  water  from the sediment/soil dewatering
                                                    process,  would be treated by filtration and carbon
                                                    adsorption  to meet discharge criteria according to
                                                    substantive requirements of NPDES.
Surface water removed prior to dredging,  along
with water from the sediment/soil dewatering
process, would be treated by  filtration  and carbon
adsorption in compliance with these  regulations.
Surface water removed prior to dredging,  along
with water from the sediment/soil dewatering
process, would be treated by  filtration  and carbon
adsorption in a manner which  is  consistent with
the antidegradation policy in the Water  Quality
Standards.

Hazardous waste determinations would be
performed an all contaminated soils/sediments
excavated to determine that levels of
regulated constituents do not exceed applicable
limits.
Also, wastes produced from surface water and
dewatering treatment would be tested to
determine whether levels of certain  regulated
constituents (lead, mercury,  heptachlor,  etc.)
exceed TCLP limits. Any contaminated
soil/sediments which exceed applicable  limits
would be managed in accordance with
requirements of these regulations, if necessary.

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                                                                       TABLE  11-3


                                                           ACTION-SPECIFIC ARARs AND TBCs
                                         ALTERNATIVE 3 -  EXCAVATION/DREDGING, ONSITE  DEWATERING, AND
                                                         OFFSITE DISPOSAL  OF  SOIL/SEDIMENT;
                                              RESTORATION  OF WETLANDS AND WATERWAYS; AND MONITORING
                                                                AREA  A DOWNSTREAM/OBDA
                                                             NSB-NLON GROTON,  CONNECTICUT
                                                                         PAGE 2  OF 2



      Requirement                         Citation           Status                       Synopsis of Requirement                         Action to Be Taken to Attain ARAR

                                                          Applicable         This section establishes standards for various         Surface water treatment residues  (spent filtration
                                                                              classes of generators. The standards  of  40  CFR         media and activated carbon)  may contain high
                                                                              2 62 are incorporated by reference.                     concentrations of certain regulated constituents
                                                                                                                                     such as lead, mercury,  heptachlor, etc.  Although
                                                                                                                                     the residues are not expected to  fail hazardous
                                                                                                                                     characteristics, substantive requirements of these
                                                                                                                                     regulations would be met.

Hazardous Waste                   RCSA  °  22a-449(c)  104   Applicable         This section establishes standards for treatment,      Any hazardous waste which may be  treated or
Management:TSDF                                                             storage, and disposal facilities. The standards  of    temporarily stored on this site as part of the
Standards                                                                     40 CFR 264 are incorporated by reference.              remedy would be managed in accordance with the
                                                                                                                                     requirements of this section.
Air Pollution Control             RCSA  °  22a-174  1-20      Applicable          These regulations require permits to construct  and    Emission standards for  fugitive dust from
                                                                               to operate specified types of emission  sources        excavation and restoration operations would be
                                                                               and contain emission standards  that  must be  met      met with dust control measures.  Odors/emissions
                                                                               prior to issuance of a permit.  Pollutant abatement    from the dewatering piles would be managed to
                                                                               controls may be required. Specific standards         comply with these standards.
                                                                               pertain to fugitive dust  (18b),  and  control  of  odors
                                                                               (23) .

                                                                                                                                     Diversions as part of site remediation are exempt
                                                                                                                                     from state diversion regulations  as long as 1)  best
                                                                                                                                     management practices are employed to minimize
                                                                                                                                     erosion and sedimentation, to provide for
                                                                                                                                     necessary downstream flow in surface waters
                                                                                                                                     affected by the diversion, and to avoid adverse
                                                                                                                                     impacts to adj acent wells and to  fish and wildlife,
                                                                                                                                     including to their spawning  and nesting seasons;
                                                                                                                                     or 2)  if such activity, structure, or facility may after
                                                                                                                                     the habitat of any rare, endangered or threatened
                                                                                                                                     species fisted or identified by any federal or state
                                                                                                                                     governmental agency, if present only. Surface
                                                                                                                                     water diversions would  be conducted using best
                                                                                                                                     management practices.
                                                                                                                                     Guidelines would be followed to protect wetlands
                                                                                                                                     and aquatic resources.

-------
11.4 UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT OR RESOURCE RECOVERY TECHNOLOGIES
TO
THE MAXIMUM EXTENT PRACTICABLE

The selected remedial action (Alternative 3) offers a greater potential for permanence than allowing the
contaminants to remain on site as in Alternative 2. Although landfill disposal without treatment is
typically not a favorable option, the nature of the primary contaminants (pesticides) is such that owing
to their minimal solubility in water, their potential for migration in the environment is minimal. The
only potential of threat to human health would be in the event of long-term exposure of landfill workers
through dermal contact or incidental ingestion of contaminated soil/sediment, which is not expected to be
of concern because permitted landfills with an established record of worker health and safety practices
will be selected.

Because of the presence of a high water table, State of Connecticut regulations do not allow onsite reuse
of treated soil unless contaminant levels are reduced to less than detection limits. Therefore, the
treated soil under Alternative 4 would have to be disposed of off site. Thus, the use of treatment as a
principal element for reduction in toxicity in Alternative 4, albeit being a more long-term effective and
permanent solution, is of guestionable benefit compared to the selected remedial action.

Resource recovery is not intended to be a component of any of the alternatives because the main
contaminant, DDTR, is a banned pesticide.

Among those alternatives that are protective of human health and environment and comply with ARARs, the
Navy, with EPA and CTDEP concurrence, have determined that this selected remedial action provides the
best balance of trade-offs in terms of long-term effectiveness and permanence; reduction in toxicity,
mobility or volume through treatment; short-term effectiveness; implementability; and cost while also
considering the statutory preference for treatment as a principal element and considering state and
community acceptance.

11.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT

The selected remedy does not treat the wastes for reduction of toxicity, mobility, or volume. However,
dewatering of the soil and sediment to the extent possible on site would render the material amenable to
easier handling and it would minimize the potential for adverse effects from releases to the environment
in the event of a spill. Also, onsite treatment of the drainage water from dewatering operations does
provide a minor reduction of contaminant toxicity and volume.

12.0 DOCUMENTATION OF NO SIGNIFICANT CHANGES

The U.S. Navy presented a Proposed Plan outlining the proposed alternative (Alternative 3) of excavation,
dewatering, and offsite landfill disposal for Area A Downstream/OBDA. The Proposed Plan was presented to
the public on August 6, 1997. Public comments have been considered by the Navy prior to the selection of
the preferred alternative. Upon review of these comments, it was determined that no significant changes
to the remedy, as originally identified in the Proposed Plan, were necessary.

13.0 STATE ROLE

The CTDEP, as a part of the FFA, has reviewed the various alternatives. The CTDEP has also reviewed the
Remedial Investigation and Feasibility Study to determine if the selected remedial action is in
compliance with applicable or relevant and appropriate state environmental laws and regulations.

The CTDEP concurs with the selected remedial action for Area A Downstream/OBDA. A copy of the letter of
concurrence is presented in Appendix B of this ROD.

-------
REFERENCES

Atlantic, 1992. Phase I Remedial Investigation Naval Submarine Base - New London, Groton, Connecticut,
August 1992. Colchester, CT.

Atlantic, 1994. Draft Focused Feasibility Study, Area A Downstream/OBDA, Installation Restoration
Program, Naval Submarine Base - New London, Groton, Connecticut, April 1994. Colchester, CT.

Atlantic, July 1994. Wetland Delineation, Area A, Naval Submarine Base - New London, Groton, Connecticut.
Colchester, CT.

B&R Environmental, March 1997. Final Phase II Remedial Investigation, Naval Subbase New London,
Connecticut, 1995/March 1996 Revision 0, Brown & Root Environmental, Pittsburgh, PA.

B&R Environmental, July 1997. Draft Final Feasibility Study, Area A Downstream/OBDA, Naval Submarine Base
- New London, Groton, Connecticut, Brown & Root Environmental, Pittsburgh, PA.

Envirodyne, 1982. Initial Assessment Study (IAS), Envirodyne Engineers, Inc., 1982.

Foster Wheeler, July 1997. Final Post Removal Report for Over-Bank Disposal Area at Naval Submarine Base,
New London, CT. July 1997 by Foster Wheeler Environmental Corporation Under Remedial Action Contract.

Long, et al. , 1995. Incidence of Adverse Biological Effects within Ranges of Chemical Concentrations in
Marine and Estuarine Sediment, Long, E.R., MacDonald, D.D., Smith, S.L., and Calder, F. D., Environmental
Management, 19:81-97.

Niering and Brawley, 1997. Functions and Values Assessment of Area A Downstream Wetlands and Water
Courses, Naval Submarine Base New London (NSB-NLON), Groton, Connecticut, William A. Niering and A.
Hunter Brawley, May 8, 1997.

U.S. EPA (United States Environmental Protection Agency) Region I, June 1989e. Draft Final Supplemental
Risk Assessment Guidance for the Superfund Program. EPA/901/5-89/001. Boston, MA.

U.S. EPA (United States Environmental Protection Agency), December 1989. Risk Assessment Guidance for
Superfund - Volume I - Human Health Evaluation Manual (Part A) - Interim Final. EPA/540/1-89/002. Office
of Emergency and Remedial Response.

U.S. EPA (United States Environmental Protection Agency), March 25, 1991e. Risk Assessment Guidance for
Superfund - Volume I: Human Health Evaluation Manual - Supplemental Guidance - "Standard Default Exposure
Factors" - Interim Final. OSWER Directive 9285.6-03. Office of Emergency and Remedial Response.

U.S. EPA (United States Environmental Protection Agency), September 1992a. Sediment Classification
Methods Compendium. EPA 823-R-92-006. Office of Water, Sediment Oversight Technical Committee,
Washington, D.C.

U.S. EPA (United States Environmental Protection Agency), 1992b. Water Quality Criteria Summary
Concentrations. Office of Science and Technology, Health and Ecological Criteria Division.

U.S. EPA (United States Environmental Protection Agency), 1992c. Framework for Ecological Risk
Assessment. EPA/630/R-92/001. Risk Assessment Forum.

U.S. EPA (Untied States Environmental Protection Agency) Region I, August 1994m. Risk Updates, Number 2.
Waste Management Division, Boston, MA.

U.S. EPA (United States Environmental Protection Agency), Region I, August 1995d. Risk Updates, Number 3.
Waste Management Division, Boston, MA.

-------
                                              APPENDIX A
                                      PUBLIC MEETING TRANSCRIPT

                                         DEPARTMENT OF THE NAVY
                                            NORTHERN DIVISION
                                  NAVAL FACILITIES ENGINEERING COMMAND
                                          10 INDUSTRIAL HIGHWAY
                                              MAIL STOP, #82
                                          LESTER, PA 19113-2090

                                        MINUTES OF PUBLIC MEETING

                                       SITE 3 - AREA A DOWNSTREAM
                                                        IN REPLY REFER TO
To:

From:


Date:

Subject:
NSB-NLON Public Meeting Attendees

 Mark Evans,  Remedial Project Manager,  Northern Division,  Naval
Facilities Engineering Command

 1 October 1997

Public Meeting Minutes - August 6, 1997
Installation Restoration Program
Naval Submarine Base - New London (NSB-NLON)
Groton, Connecticut.
Attendees of the meeting

Andy Stackpole
Mark Evans
Greta Deirocini
Kymberlee Keckler
Patti Lynne Tyler
David Peterson
Jennifer Hayes
Mark Lewis
Corey Rich
J. P. Pradeep
Susan Orrill
Andrew Parella
Bart Pearson
Steve Cicoria
L. J. Chmura
Dave Paskavsky
Felix Prokop III
Dr. Norman Richards
Noah Levine
               NSB-NLON
               Navy
              Navy
              USEPA Boston
              USEPA Boston
              USEPA Boston
              Gannett Fleming
              CTDEP
              Brown & Root
              Brown & Root
              RAB Community Co-Chair
              RAB Member
              Community
              Community
              Community (City of Groton Conservation Commission)
              Community (City of Groton Conservation Commission)
              Community (Ledge Light Health District)
              Community (The Mohegan Tribe of Indians of Connecticut)
              Community

-------
Welcome and Introduction

Andy Stackpole opened the meeting at 6:30 p.m..

Mr. Stackpole read the public notice that appeared in the New London Day on August 1, 1997.

Mr. L. J. Chmura stated that the law in the State of Connecticut reguires a 30-day legal notice, and all
he ever saw was an advertisement without a legal notice number on it, and he went to the Groton Library
that day, the day after, and yesterday, and there was no literature there from the Navy regarding this
meeting.

Mr. Stackpole stated that he went to the library the day before this noticed was published and made sure
the information was there.

Mr. Chmura asked why they weren't given a 30-day notice as reguired by law.

Mr. Stackpole stated that the Navy put a legal ad in the paper (New London Day) on August 1 and the Navy
is having a public comment period until September 2. The Navy has a legally stamped notarized copy from
the New London Day certifying that the notice was placed in the paper on August 1, 1997.

Mr. Chmura asked if there was a legal number on it.

Mr. Stackpole stated that the reguirement is for the Navy to publish a notice in a major local newspaper
and the Navy met that reguirement.

Mr. Chmura stated that it is suppose to be a 30-day notice before the hearing.

Mr. Dave Paskavsky stated that you may be the Navy but you got to still play by the rules.

Andy Stackpole stated that the Navy follows applicable regulations.

(Mr. J. P. Pradeep gave presentation on the Proposed Plan for the Area A Downstream).

Mr. Paskavsky asked who conducted this investigation, were borings taken and were any lead batteries
found.

Mr. Pradeep stated Brown & Root Environmental, the Navy consultant, conducted the investigation. No lead
batteries were found and soil borings were conducted.

Mr. Paskavsky asked how deep the boring were taken.

Mr. Mark Evans stated that borings were taken up to 80 feet deep and there were no lead batteries found
there. The site that we are discussing is the Area A Downstream not the Area A Landfill. This area is
below a large man-made dike that was constructed back in the '40s during the dredging of the Thames
River.

Ms. Patti Lynne Tyler stated that the Area "A" Downstream is almost all wetlands.

Mr. Paskavsky asked whether the area was filled in the early '40s.

Mr. Pradeep stated that dredge spoils were placed in the Area "A1 wetlands, and the area we're talking
about is downstream of this Area "A" wetland and landfill. It's a series of ponds and streams and
wetlands.

Mr. Chmura asked if this area was used as a dump for the things that they wanted to get rid of at the
base.

Mr. Evans stated that there were no dumping operations in this area. The Navy used a pesticide called DDT
to control the mosguito population, and that is the contaminant that is the concern in this area.

Mr. Stackpole stated that this area is where the dike was built. This area was virtually untouched. There
are a few areas in here that there was never any kind of filling or land filling going on.

Mr. Chmura asked if the scrap metal or anything like that was disposed of here.

Mr. Stackpole stated that no industrial waste was disposed of there.

-------
(Mr. Pradeep continued the presentation on the proposed remedial action for Area "A" Downstream).

Mr. Pradeep stated that additional information can be found in the Groton Public Library.

Mr. Paskavsky stated that they don't have a copy of the report and asked to receive a copy.

Mr. Pradeep gave Mr. Paskavsky a copy of the Feasibility Study.

Mr. Noah Levine stated that he was on the Navy's mailing list, but did not get a notice in the mail. He
hasn't received anything since last year. It just so happens that he caught this in the paper.

Ms. Sue Orrill stated that the Navy has been meeting with the public for over ten years. It started as a
technical review committee which reviews some of these documents. This has been going on as early as the
1980s. She stated that she is a resident of Gales Ferry and a member of the technical review committee
which was later renamed the Restoration Advisory Board. The board usually meets four times a year or
every three
months depending on when certain public meetings are being held. We can't beg enough people to come. If
your interested, we'll let you know when the next meeting is.

Mr. Paskavsky stated that he was interested.

Ms. Orrill asked if he would put that on the address list that you may be interested in joining the
restoration advisory board. So, if you are interested that's what we're trying to do, make sure that the
information is getting examined by the public and comments get made. It was six months ago that 250
letters were sent out about the RAB meeting.

Mr. Levine stated that the last one he went to was last year.

Ms. Orrill stated that it's good that this gets publicized. The defensiveness that I hear coming from the
public at large I really don't understand. That's the whole purpose of the restoration advisory board
members. I'm the Co-chairman and the non-Navy person community member at large. So, I've had calls and
given out the information. I usually have a personal copy of the documents. I've lent those out to make
it easier than going to the library.

Mr. Bart Pearson stated that when the meetings first started the medical officer from the City use to
attend the meetings, and then for some reason we haven't seen him for a long time.

(Patti Lynne Tyler from EPA gave a presentation on the development of Preliminary Remediation Goals).

Mr. Chmura asked if this area drains into the Thames River.

Mr. Paskavsky asked if any of it goes into the Groton reservoir.

Ms. Tyler stated that it does not drain into the Groton reservoir, but Stream 5 eventually comes out and
drains into the Thames River and the same with Stream 6, so they do eventually drain into the Thames
River.

Mr. Paskavsky asked how long does it take for DDT to break down and go away.

Ms. Tyler stated that it takes many, many years. U.S. Fish and Wildlife services continues to monitor
fish from the Great Lakes area and they still see very high concentrations. What you end up seeing is you
don't have as much DDT but you get the breakdown products like DDE which is a lower toxic, but was
responsible for the eggshell thinning of the Bald Eagles.

(Ms. Tyler continued her presentation).

Mr. Paskavsky asked if there are problems with PCBs.

Ms. Tyler stated no.

Mr. Chmura asked if the Navy tested for dioxins.

Ms. Tyler stated that the Navy did. We're looking for pesticides. We are able to show that pesticides are
driving the risks and looking at clean-up goals for inorganics.

Dr. Norman Richards asked looking back, what information do you think you would have gotten with
sulfides, with the metals that you found.

-------
Ms. Tyler stated that they wouldn't have been available. Looking at the concentrations of the pesticides
by far drives the risk. There's no question about it at all, and the toxicity tests we have are 100
percent across the board. What I would like to mention is we are going into an area that is a wetland.
We're going to have to excavate and destroy that area. We will restore that area in kind and in place.
That area has been delineated. It will include regrading, replanting, and restoring that wetland.

Dr. Richards asked if that will be in a one-to-one ratio.

Ms. Tyler stated yes in kind and in place, same footprint.

Mr. Paskavsky asked what the Navy is going to do with the soil that is cleaned out of the ponds.

Ms. Tyler stated that it depends on what's in the sediments or the soils. If it has high concentrations
of DDT, it will be brought to an outside hazardous waste landfill.

Mr. Chmura asked what caused such a concentration of DDT in that particular wetland.

Ms. Tyler stated that they used DDT for mosguito control.

Mr. Chmura asked how did the Navy get rid of that in that other area, the Area "A1 wetlands.

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                                           APPENDIX B

                                 CTDEP CONCURRENCE WITH PROPOSED PLAN


                                              APPENDIX C

                                        RESPONSIVENESS SUMMARY

The Navy published a notice and brief analysis of the Proposed Plan in the New London Day on August 1,
1997 and made the plan and the administrative record available to the public at the Groton Public
Library, the Bill Library and the Naval Submarine Base Library.

On August 6, 1997, the Navy held an informational meeting to discuss and present the Proposed Plan. Also,
on August 6, 1997 the Navy held a public hearing to discuss the Proposed Plan and to accept any oral
comments. A transcript of this meeting is included in Appendix A. From August 1, 1997 to September 1,
1997 the Navy held a 30-day public comment period to accept public comment on the Proposed Plan.

SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD

Oral comments received during the public hearing held on August 6, 1997 are provided in Appendix A. No
written comments were received during the public comment period other than a letter dated August 18, 1997
from the Connecticut Department of Environmental Protection (CTDEP) expressing their support of the
Proposed Plan as presented.


                                              APPENDIX D

                                      DECLARATION OF CONCURRENCE


The State of Connecticut has concurred with the Proposed Remedial Action Plan as shown in Appendix B. The
U.S. EPA has concurred with the Proposed Plan as described in the Declaration of this Record of Decision.

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